Part 2 out of 5
The possibilities of working up a local trade of high grade eggs at
fancy prices varies greatly with the locality. Large cities and
wealthy people are essentials. Other than this the principal
distinctions are that regions where a general surplus of eggs are
produced offer little chance for a fancy trade. Where the great bulk
of eggs are imported fancy trade is more feasible. St. Louis is the
smallest western city that supports anything like a fancy trade in
eggs and there it is only on a small scale. Minneapolis, Omaha,
etc., would not pay 3 cents premium for the best eggs produced, but
cities of the same size east of the Appalachians and especially in
New England, will pay a good premium. The Far West or the mountain
districts will pay up better than the Mississippi Valley. The South
will pay a little better than the upper Mississippi Valley, but has
few cities of sufficient size to make such markets abundant. The
Southerner has little regard for quality in produce and the most
aristocratic people consume eggs regularly that the wife of a
Connecticut factory hand wouldn't have in the house. The egg farmer
who expects to sell locally had best not locate south of Washington
or west of Pittsburg, unless he goes to the Pacific Coast.
Where marketing is not done by wagon the subject of railroad
transportation is practically identical with the question of
marketing. It is the cost in freight service and freight rates that
count. The proposition of transportation, especially for the grain
buying poultry farm, catches us coming and going and both must be
A poultry farm in Section 7 will buy one hundred pounds of feed per
year per hen and market one-third of a case of eggs. On this basis
the grain rate from Chicago or St. Louis and the egg rate to New
York must be balanced against each other. Don't take these things
for granted. Look them up.
Jamesburg and Freehold, two New Jersey towns ten miles apart and
equi-distant and with equal freight rates from New York, might seem
to the uninitiated as equally well situated to poultry farming. We
will suppose two men bought forty-acre farms of equal quality and
equi-distant from the railroad stations at these two towns. Suppose,
further, they each kept five thousand hens. Jamesburg is on a
Philadelphia-New York line of the Pennsylvania and its Chicago grain
rate is the same as that of New York, namely: 19-1/2 cents per
hundred. Freehold is on a branch line; its rate is 24-1/2 cents. In
a year the difference amounts to $250. Figured at six per cent.
interest, the land at Jamesburg is worth just about one hundred
dollars an acre more than that at Freehold.
Lumber rates or local lumber prices should also be taken into
consideration. Whether one plans to ship his product out by express
or freight will, of course, be an important consideration in
deciding the location.
As a general thing, the individual poultry farmer will, for shipping
his product, use express east of Buffalo and north of Norfolk. The
poultry community could use freight in these same regions and get as
good or better service than by express.
The location in relation to the railroad station is equally
important to the freight rate. Besides heavy hauling frequent trips
will be necessary in marketing eggs. These on the larger farms will
be daily or at least semi-weekly. On the heavy hauling alone, at 25
cents per ton mile, distance from the railroad will figure up 1-1/4
cents per hen which, on the basis of the previous illustration,
would make a difference of twenty-five dollars per acre for every
mile of distance from the station. One of the most successful
poultry farms I know is right along the railroad and has an elevator
which handles the grain from the cars and later dumps it into the
feed wagons without its ever being touched by hand. The labor saving
in this counts up rapidly.
The poultry community can have its own elevator and the grain can be
sold to the farmer to be delivered directly into the hoppers in his
field with but a single loading into a wagon.
Availability of Water.
One more point to be considered in location is water.
The labor of watering poultry by carrying water in buckets is
tremendous and not to be considered on any up-to-date poultry plant.
Watering must be accomplished by some artificial piping system or
from spring-fed brooks. The more length of flowing streams on a
piece of land, provided the adjacent ground is dry, the more value
the property has for poultry. Two spring-fed brooks crossing a
forty-acre tract so as to give a half mile of running water, or a
full mile of houses, would water five thousand hens without labor.
This would mean an annual saving of at least one man's time as
against hand watering, or a matter of a thousand dollars or more in
the cost of installation of a watering system.
If running water cannot be had the next best thing is to get land
with water near the surface which may be tapped with sand points. If
one must go deep for water a large flow is essential so that one
power pump may easily supply sufficient water for the plant.
The land should lay in a gentle slope so that water may be run over
the entire surface by gravity. Hilly lands are a nuisance in poultry
keeping and raise the expense at every turn.
A Few Statistics.
The following table does not bear directly upon the poultry-man's
choice of a location, but is inserted here because of its general
interest in showing the poultry development of the country.
It will be noted that the egg production per hen is very low in the
Southern States. This may seem at variance with my previous
statements. The poor poultry keeping of the South is a fault of the
industrial conditions, not of the climate. Chickens on the Southern
farm simply live around the premises as do rats or English sparrows.
No grain is grown; there are no feed lots to run to, no measures are
taken to keep down vermin, and no protection is provided from wind
and rain. In the North chickens could not exist with such treatment.
The figures given showing the relation between the poultry and total
agricultural wealth is the best way that can be found to express
statistically the importance of poultry keeping in relation to the
general business of farming. These figures should not be confused
with the distribution of the actual volume of poultry products.
Iowa, the greatest poultry producing state, shows only a moderate
proportion of poultry to all farm wealth, but this is because more
agricultural wealth is produced in Iowa than in all the "Down East"
Table showing the development of the poultry industry in the various
states, according to the returns of the census of 1900:
No. of Percentage of No. of Farm value
eggs per farm wealth eggs of eggs per
capita earned by per hen dozen
Alabama 124 4.9 48 9.7 cents
Arizona 80 4.5 60 19.9
Arkansas 235 6.8 58 9.1
California 197 5.4 74 15.8
Colorado 127 5.4 71 15.0
Connecticut 105 11.3 89 19.1
Delaware 231 14.7 68 13.7
Florida 96 8.2 46 13.1
Georgia 156 4.4 41 10.4
Idaho 213 5.0 67 16.2
Indiana 338 10.0 77 10.5
Iowa 536 7.4 64 10.1
Illinois 215 3.7 62 10.3
Kansas 597 8.2 73 9.9
Kentucky 198 8.3 62 9.8
Louisiana 111 4.0 40 10.0
Maine 233 11.0 100 15.3
Maryland 126 10.4 71 12.6
Massachusetts 56 11.7 96 19.9
Michigan 270 9.7 82 11.2
Minnesota 296 5.8 67 10.5
Mississippi 144 4.7 43 9.9
Missouri 291 11.6 68 9.8
Montana 148 4.3 67 21.0
Nebraska 463 6.1 66 9.9
Nevada 68 3.7 71 20.8
New Hampshire 238 11.5 96 17.3
New Jersey 76 12.0 72 16.2
New Mexico 45 2.7 65 18.7
New York 102 7.1 83 13.9
North Carolina 112 5.7 55 10.2
North Dakota 249 2.6 64 10.5
Ohio 265 9.6 77 11.2
Oklahoma 315 6.4 60 9.3
Oregon 224 6.2 72 15.1
Pennsylvania 112 10.8 75 13.5
Rhode Island 90 19.7 77 20.4
South Carolina 80 4.0 41 10.3
South Dakota 502 5.2 68 10.0
Tennessee 189 8.4 61 9.8
Texas 228 4.8 52 8.0
Utah 146 5.1 76 12.5
Vermont 219 7.5 94 15.3
Virginia 165 8.9 67 11.1
Washington 171 7.1 74 16.8
West Virginia 216 10.2 74 10.9
Wisconsin 268 7.1 68 10.5
Wyoming 121 2.4 79 17.4
Entire U.S. 205 7.4 65 11.1
THE DOLLAR HEN FARM
As has already been emphasized, the way to get money out of the
chicken business is not to put so much in.
Land, however, well suited to the purpose, should not be begrudged,
for interest at six per cent, will afford a very considerable extra
investment in land well suited to the business if it in any way cuts
down the cost of operation.
The Plan of Housing.
The houses are the next consideration. On most poultry farms they
are the chief items of expense. I know of a poultry farm near New
York City where the house cost $12.00 per hen. The owner built this
farm with a view of making money. People also buy stock in Nevada
gold mines with a view of making money. I know another poultry farm
owned by a man named Tillinghast at Vernon, Connecticut, where the
houses cost thirty cents per hen. Mr. Tillinghast gets more eggs per
hen than the New York man. Incidentally, he is sending his son to
Yale, and he has no other visible means of support except his
For the region of light soils and the localities which I have
recommended for poultry farming, the following style of poultry
house should be used:
No floors, single boarded walls, a roof of matched cypress lumber or
of cheap pine covered with tarred paper. This house is to have no
windows and no door. The roosts are in the back end; the front end
is open or partly open; feed hoppers and nests are in the front end.
The feed hoppers may be made in the walls, made loose to set in the
house, or made to shed water and placed outside the house. All
watering is to be done outside the houses; likewise any feeding
beyond that done in hoppers.
The exact style of the house I leave to the reader's own plan. Were
I recommending complex houses costing several dollars per hen, this
certainly would be leaving the reader in the dark woods. With houses
of the kind described it is hard to go far amiss. The simplest form
is a double pitched roof, the ridge-pole standing about seven feet
high, and the walls about four. The house is made eight by sixteen,
and one end--not the side--left open. For the house that man is to
enter, this form cannot be improved upon.
The only other points are to construct it on a couple of 4x4 runners
so that it can be dragged about by a team. Cypress, or other
decay-proof wood should be used for these mud-sills. The framing
should be light and as little of it used as is consistent with
firmness. If the whole house costs more than twenty-five dollars
there is something wrong in its planning.
This house should accommodate seventy-five or eighty hens.
For smaller operations, especially for horseless, or intensive
farming, a low, light house may be used, which the attendant never
enters. A portion of the roof lifts up to fill feed-hoppers, gather
eggs or spray. These small houses may be made light enough to be
moved short distances by a pry-pole, the team being required only
when they are moved to a new field.
Not one particle of poultry manure is to be removed from either
style of house. Instead, the houses are removed from the manure,
which is then scattered on the neighboring ground with a fork, or,
if desired to be used on a field in which poultry may not run, it
may be loaded upon a wagon together with some of the underlaying
There have been books and books written on poultry houses, but what
I have just given is sufficient poultry-house knowledge for the
Dollar Hen man. If he hasn't enough intelligence to put this into
practice, he has no business in the hen business. Additional
book-knowledge of hen-houses is useless; it may be harmful.
If you are sure that you are fool-proof, you may get Dr. Feather or
Reverend Earlobe's "Book of Poultry House Plans." It will be a good
text-book for the children's drawing lessons.
The Feeding System.
Oyster shells, beef scraps, corn, and one other kind of grain,
together with an abundance of pasturage or green feed, is the sum
and substance of feeding hens on the Dollar Hen Farm.
The dry feeds are placed in hoppers. They are built to protect the
feeds from the weather. The neck must be sufficiently large to
prevent clogging, and the hopper so protected by slats in front that
the hen cannot toss the feed out by a side jerk of her head. These
hoppers may be built any size desired. The grain compartments
should, of course, be made larger than the others. Weekly filling is
good, but where a team is not owned, it would be better to have the
hoppers larger so that feed purchased, say, once a month, could be
delivered directly into the hoppers.
The best water system is a spring-fed brook.
The man proposing to establish an individual poultry plant, and who
after reading this book goes and buys a tract of land where an
artificial water system is necessary, would catch Mississippi
drift-wood on shares. But there are plenty of such people in the
world. A man once stood all day on London Bridge hawking gold
sovereigns at a shilling a-piece and did not make a sale.
Next to natural streams are the made streams. This is the logical
watering method of the community of poultry farmers. These
artificial streams are to be made by conducting the water of natural
streams back of the land to be watered, as in irrigation. It is the
problem of irrigation over again. Indeed, where trucking is combined
with poultry-growing, fowl watering should be combined with
It may be necessary to dam the stream to get head, sufficient supply
or both. In sandy soils, ditches leak, and board flumes must be
substituted. The larger ones are made of the boards at right angles
and tapered so that one end of one trough rests in the upper end of
the next lower section. The smaller, or lateral troughs may be made
The cost of the smaller sized flume is three cents a foot. Iron pipe
costs twelve cents a foot.
The greater the slope of the ground the smaller may be the troughs,
but on ground where the slopes are great, more expense will be
necessary in stilting the flumes to maintain the level, and the
harder it will be to find a large section that can be brought under
Fluming water for poultry is, like irrigation, a community project.
The greatest dominating people of history have their origin in arid
countries. It was co-operate or starve, and they learned
co-operation and conquered the earth. If a man interferes with the
flume, or takes more than his share of the water, put him out. We
are in the hen, not the hog business.
Community water systems, where water must be pumped and piped in
iron pipe, is of course a more expensive undertaking. It will only
pay where water is too deep for individuals to drive sand points on
their own property. There is certainly little reason to consider an
expensive method when there are abundant localities where simple
plans may be used.
On sand lands, with water near the surface, each farmer may drive
sand points and pump his water by hand. In this case running water
is not possible, but the pipes or flumes may be arranged so that
fresh pumping flushes all the drinking places and also leaves them
full of standing water. The simplest way to arrange this will be by
wooden surface troughs as used in the fluming scheme. The only
difference is that an occasional section is made deeper so that it
will retain water.
A more permanent arrangement may be made by using a line of
three-fourths inch pipe. At each watering place the pipe is brought
to the surface so that the water flows into a galvanized pan with
sloping sides. This pan has an overflow through a short section of
smaller tubing soldered to the side of the pan. The pipe line is
parallel with the fence line, the pans supply both fields. By this
arrangement the entire plant may be watered in a few minutes. The
overflow tubes are on one side. Using these tubes as a pivot the
pans may be swung out from under the fence with the foot and cleaned
with an old broom. Where the ground water is deep a wind mill and
storage tank would be desirable.
The hen house is a place for roosting, laying and a protection for
the feed. The hen is to live out doors.
On the most successful New England poultry farms, warm houses for
hens have been given up. Hens fare better out of doors in Virginia
than they do in New England, but make more profit out of doors
anywhere than they will shut up in houses. If your climate will not
permit your hen to live out doors get out of the climate or get out
of the hen business.
There is, however, a vast difference in the kind of out-of-doors.
The running stream with its fringe of trees, brush and rank growing
grass, forms daylight quarters for the hen par excellence. Rank
growing crops, fodder piled against the fences, a board fence on the
north side of the lot, or little sheds made by propping a platform
against a stake, will all help. A place out of the wind for the hens
to dust and sun and be sociable is what is wanted, and what must be
provided, preferably by Nature, if not by Nature then by the
The hens are to be kept as much as possible out of the houses, in
sheltered places among the crops or brush. They should not herd
together in a few places but should be separated in little clumps
well scattered over the land. These hiding places for the hens must,
of course, not be too secluded or eggs will be lost.
Equipment for Chick Rearing.
Just as the long houses for hens have been weighed and found
wanting, so larger brooder houses, with one exception, have never
been established on what may be called a successful basis. By
establishment on a successful basis, I mean established so that they
could be used by larger numbers of people in rearing market
chickens. There are plenty of large brooder houses in use, just as
there are plenty of yarded poultry plants, but many intelligent,
industrious people have tried both systems only to find that the
cost of production exceeds the selling price. This makes us prone to
believe that some of those who claim to be succeeding may differ
from the crowd in that they had more capital to begin with and hence
The one exception I make to this is that of the South Shore Roaster
District of Massachusetts. Here steam-pipe brooder houses are used
quite extensively. The logical reason that pipe brooder houses have
found use in the winter chicken business and not in rearing pullets
is that of season and profits. When chicks are to be hatched in the
dead of winter the steam-heated brooder house is a necessity. In
this limited use it is all right, where the profits per chick are
great enough to stand the expense and losses.
For the rearing of the great bulk of spring chicks the methods that
have proven profitable are as follows:
First: Rearing with hens as practiced at Little Compton. For
suggestions on this see the chapter entitled "Poultry on the General
Second: Rearing with lamp brooder. Many large book-built poultry
plants have been equipped with steam, or, more properly, hot water
heated brooder houses, only to have a practical manager see that
they did not work, tear out the piping and fill the house with rows
of common lamp brooders. The advantage claimed for the lamp brooder
is that they can be regulated separately for each flock. As a matter
of fact, the same regulation for each flock of chicks could be
secured with a proper type of hot water heaters and one of the most
practical poultry farms in the country is now installing such a
A brooder system where hot air under the pressure of a blower or
centrifugal fan would seem ideal. So far the efforts made along
these lines have been clumsy and unnecessarily expensive. If the
continuous house is ever made practical, I believe it will be along
this line, but at present I advise sticking to the methods that are
known to be successful.
Individual lamp brooders in colony houses are perhaps the most
generally successful means of rearing chicks on northern poultry
farms. They are troublesome and somewhat expensive, but with
properly hatched chickens are more successful than hen rearing. In
buying such a brooder the chief points to be observed are: A good
lamp, a heating device giving off the heat from a central drum, and
an arrangement which facilitates easy cleaning. The brooder should
be large, having not less than nine square feet of floor space. The
work demanded of a brooder is not as exacting as with an incubator.
The heat and circulation of air may vary a little without harm, but
they must not fail altogether. The greatest trouble with brooders in
operation is the uncertainty of the lamp. The brooder-lamp should
have sufficient oil capacity and a large wick. Brooder-lamps are
often exposed to the wind, and, if cheaply constructed or poorly
enclosed, the result will be a chilled brood of chicks, or perhaps a
The chief thing sought in the internal arrangements of a brooder is
a provision to keep the chicks from piling up and smothering each
other as they crowd toward the source of heat. This can be
accomplished by having the warmest part of the brooder in the center
rather than at the side or corner. If the heat comes from above and
a considerable portion of the brooder be heated to the same
temperature, no crowding will take place.
The temperature given for running brooders vary with the machine and
the position of the thermometer. The one reliable guide for
temperature is the action of the chicks. If they are cold they will
crowd toward the source of heat; if too warm they will wander
uneasily about; but if the temperature is right, each chick will
sleep stretched out on the floor. The cold chicken does not sleep at
all, but puts in its time fighting its way toward the source of
heat. In an improperly constructed or improperly run brooder the
chicks go through a varying process of chilling, sweating and
struggling when they should be sleeping, and the result is puny
chicks that dwindle and die.
The arrangement of the brooder for the sleeping accommodations of
the chicks is important, but this is not the only thing to be
considered in a brooder. The brooder used in the early season, and
especially the outdoor brooder, must have ample space provided for
the daytime accommodation of the chick. In the colony house brooder
such space will, of course, be the floor of the house.
When operating on a large scale it will not pay to buy complete
brooders. The lamps and hovers can be purchased separately and
installed in colony houses which do both for brooders and later for
houses for growing young stock. The universal hover sold by the
Prairie State Incubator people is about as perfect a lamp hover as
can be made.
The cold brooder, or Philo box, as it has been popularly called, is
the chief item in a system of poultry keeping that has been widely
advertised. The principle of the Philo box is that of holding the
air warmed by the chick down close to them by a sagging piece of
cloth. The cloth checks most of the radiating heat, but is not so
tight as to smother the chick. This limits the space of air to be
warmed by the chicks to such a degree that the body warmth is used
to the greatest advantage. That chickens can be raised in these
fire-less brooders, is not in question, for that has been abundantly
proven, but most poultrymen believe that it will pay better,
especially in the North, to give the little fellows a few weeks'
Curtis Bros. at Ransomville, N.Y., who raise some twenty thousand
chicks per year, have adopted the following system: The chicks are
kept under hovers heated by hot water pipes for one week, or until
they learn to hover. Then they are put in Philo boxes for a week in
the same building but away from the pipes. The third week the Philo
boxes are placed in a large, unheated room. After that they go to a
large Philo box in a colony house.
To make a Philo house of the Curtis pattern, take a box 5 in. deep
and 18 in. to 24 in. square. Cut a hole in one side for a chick
door, run a strip of screen around the inside of the box to round
the corners. Now take a second similar box. Tack a piece of cloth
rather loosely across its open face. Bore a few augur holes in the
sides of either box. Invert box No. 2 upon box No. 1. This we will
call a Curtis box. It costs about fifteen cents and should
accommodate fifty to seventy-five chicks.
A universal hover in a colony coop or colony house, for which a
Curtis box is substituted, as early in the game as the weather
permits, is the method I advise for rearing young chicks. The lamp
problem we still have with us, but it is one that cannot be easily
solved. Large vessels or tanks of water which are regularly warmed
by injection of steam from a movable boiler, offers a possible way
out of the difficulty. On a plant large enough to keep one man
continually at this work, this plan might be an improvement over
filling lamps, but for the smaller plant it is lamps, or go south.
Rearing young chicks is the hardest part of the poultry business.
There is a lot of work about it that cannot be gotten rid of. Little
chicks must be kept comfortable and their water and feed for the
first few days must needs be given largely by hand. They are to be
early led to drink from the regular water vessels and eat from the
hoppers, but this takes time and patience.
The feeding of chicks I will discuss in the chapter on "Poultry on
the General Farm," and as the same methods apply in both cases, I
will refer the reader to that section.
After chicks get three or four weeks old their care is the simplest
part of the poultry farm work and consists chiefly of filling feed
hoppers and protecting them from vermin and thieves.
Board floor colony houses are used as a protection against rats and
this danger necessitates the protection of the opening by netting
and the closing of the doors at night.
Cockerels must be gotten out of the flocks and sold at an early age.
Those that are to be kept for sale or use as breeding birds should
be early separated from the pullets. Coops for growing chickens,
especially Leghorns, cannot be put among trees, as the birds will
learn to roost in the trees, causing no end of trouble to get them
broken of the habit.
All pullets save a few culls should be saved for laying. They are to
be kept two years. They should lay sixty-five to seventy per cent as
many eggs the second year as the first. They are sold the third
summer to make room for the growing stock.
Twenty-five Acre Poultry Farms.
This section will be devoted to a general discussion of the type of
poultry farms best suited to Section 4 and the southerly portions of
Section 7 as discussed in the previous chapter.
We will discuss this type of farm with this assumption: That they
are to be developed in large numbers by co-operative or corporate
effort. This does not infer that they cannot be developed by
individual effort, and nine-tenths of the operations will remain the
same in the latter case.
Suppose a large tract of land adjacent to railroad facilities has
been found. The land in the original survey should be divided into
long, relatively narrow strips, lying at right angles to the slope
of the land. The farmstead should occupy the highest end of the
strip. For a twenty-five acre or one-man poultry farm these strips
should be about forty rods in width. The object of this survey is to
permit the water being run by gravity to the entire farm.
The first thing is the farmstead, including such orchard and garden
as are desired. This stretches across the entire front end of the
place. The remainder of the strip is fenced in with chicken fence.
The farm is also divided into two narrow fields by a fence down the
center of the strip. This fence, at frequent intervals, has
The year's season we will begin late in the fall. All layers are in
field No. 1 pasturing on rape, top turnips or other fall crops. In
lot No. 2 is growing wheat or rye. As the green feed gets short in
the first lot the hens are let into lot No. 2. Sometime in March the
houses that have been brought up close to the gaps are drawn through
into the wheat field. The feed hoppers are also gradually moved and
the hens find themselves confined in lot No. 2 without any serious
Lot No. 1 is broken up as soon as weather permits and planted in
oats, corn, Kaffir corn and perhaps a few sunflowers. The oats form
a little strip near the coops and watering places and the Kaffir
corn is on the far side. As soon as corn planting is over the farmer
begins to receive his chickens from the hatchery. The brooders are
now placed in the corn field. The object of the corn is not green
food but for a shade and a grain crop.
The chicks are summered in the corn field and the hens in the wheat
or rye. Whether the latter will head up will depend upon the number
of the flock. It will be best to work the houses across to the far
side and let that portion near the middle fence head up. As the old
grain gets too tough for green food strips of ground should be
broken up and sown in oats. The grain that matures will not be cut,
but the hens will be allowed to thresh it out. The straw may be cut
with mower or scythe for use as nesting material.
Sometime in June or early in July a little rape vetch or cow-peas is
drilled in between the rows of corn as on the far side from the
chicken coops. During July or about the first of August, after all
cockerels have been sold, the gates are opened and the pullets are
allowed to associate with the hens. After this acquaintance ripens
into friendship the hen houses are worked back into the pullet lots.
Surplus hens are sold off or new houses inserted as the case may be
until there is room for the pullets in the houses. Each coop is
worked up alongside a house and after most of the pullets have taken
to the houses the coops are removed. The vacant lot is now broken up
and sown in a mixture of fall green crops.
The flock is kept in the corn field until the corn is ripe. The
Kaffir corn and sunflowers are knocked down where they stand and are
threshed by the hens. As soon as the corn crop is ripe the houses
are run back and the corn cut up or husked and the wheat planted in
the corn field.
The next year the lots are transposed, the young stock being grown
in the lot that had the hens the previous year.
If the ground is inclined to be at all damp when the fields are
broken up the plowing is done in narrow lands so as to form a
succession of ridges, on which are placed the coops or houses. The
directions of these ridges will be determined by the lay of the
land--the object being neither to dam up water or to encourage
washing. The location of the ridges are alternated by seasons, so
that the droppings from the houses are well distributed throughout
This system with the particular crops found that do best in the
locality, give us an ideal method of poultry husbandry. We have kept
hens and young stock supplied with green food the year round; we
have utilized every particle of manure without one bit of labor. We
have a rotation of crops. We have the benefits to the ground of
several green crops turned under. We have raised one grain crop per
year on most of the ground. We have no labor in feeding and watering
except the keeping of the grain, beef and grit hoppers filled, and
the water system in order.
The number of fowls that may be kept per acre will be determined by
the richness of the soil. The chief object of the entire scheme is
to provide abundant green pasture at all times and to allow the
production of a reasonable amount of grain. With one hundred hens
per acre on the entire tract, and with houses containing eighty hens
each, it will be necessary to set the houses ninety-five feet apart.
This will give the flock a tract of 95 by 330 feet in which to
The above estimate with a little land allowed for house, garden,
orchard and a little cow and team pasture, will permit the keeping
of two thousand hens on a twenty-five acre farm. In regions where
grain is to be raised most farmers would want more land. They may
also wish to own a few extra cows, hogs, etc., or to alternate the
entire poultry operations with some crop that will, on such highly
fertilized land, give a good cash profit. Forty acres is a good size
for such uses.
The cost of land when purchased in large tracts in Virginia is very
small, but the cost of clearing is often much more than that of the
land. Twenty-five to fifty dollars an acre should secure such a
tract of land and put it in shape for poultry farming.
The cost of the farm home, etc., will, of course vary altogether
with the taste of the occupant. If they are constructed by a central
company, from five hundred to a thousand dollars should cover the
The cost of poultry buildings and equipment used on the farm will
depend largely on the efficiency of the labor of construction. If
constructed in large numbers by a central company, the cost would be
reduced, but the company would expect to make a profit on their
A plot laid out for two thousand hens will require in material: 250
rods of fence with 6-ft. netting which should cost about fifty cents
a rod. My estimate of this fence put up would be $150. If the
neighboring field contained no other poultry, a portion of this
fence might be done away with, although its protection against dogs
and strangers may be worth while. Of course, if poultry fields of
different owners lay adjoining, the fence must be used, but the cost
will be reduced one-half.
The next most expensive piece of equipment will be a line of about
eighty rods of 3/4 in. gas pipe and about fifty elbows and
twenty-five galvanized iron pans. The cost of installation will
depend largely on how deep it is necessary to go to get below the
frost line. One hundred and seventy-five dollars should cover cost
of material and by the use of a plow the line ought to be put in for
The source of water, and the cost of getting a head, will
necessarily vary with the location. The installation of a wind mill
and tank to hold supply for several days, or of a small gasoline
engine, would cost in the neighborhood of one hundred dollars, but
it is a luxury that may be dispensed with if the well is not too
The houses for the hens, of which there are twenty-five, are
constructed in accordance with some of the plans previously
discussed. The cost should be about twenty-five cents per hen.
At least twice as many brooders as colony coops will be needed as
there are hen houses, but of the lamps and hovers not over
twenty-five will be required, as the chicks soon outgrow the need of
This makes a list of equipment required for the keeping of two
thousand layers and their replenishing:
25 acres of farm land, at $50 per acre $1250.00
250 rods of fence 150.00
One farmstead 1000.00
One team, plow and farm implements 300.00
One watering system 300.00
25 hen houses, at $20 500.00
50 colony coops, at $2.50 150.00
25 lamps and hovers, at $5 125.00
[Transcriber's note: "50 colony coops, at $2.50" is $125.00, not
$150. The total should therefore be $3750 rather than $3775. This
was, presumably, a printing error, because the correct total is
used in the further calculations below.]
This is a good, liberal capitalization. The business can be started
with much less. Figured interest at 6 per cent. we have $225.00 per
The upkeep of the plant will be about 15 per cent. on the capital,
not counting land. This equals $375, which, added to interest, gives
an annual overhead expense of $600, which is our first item to be
set against gross receipts.
The cost of operation will involve cost of chicks at hatchery,
purchased feed, seed for ground, and feed for team.
The price of chicks at the Petaluma hatcheries is from six to eight
cents each. We expect to raise enough pullets to make up for the
accidental losses, and to renew bulk of the flock each year. The
number required will, of course, depend upon the loss. This loss
will be much less when the chicks are obtained from a modern
moisture controlled hatchery, than from the box type incubator. I
think a 33 per cent. loss is a liberal estimate, but as I am
treading on unproven ground, I will make that loss 40 per cent.,
which is on a par with old style methods. To replace 1,000 hens,
this will require 3,500 chicks at a cost of about two hundred and
Green pasturage throughout the year will materially cut down the
cost of feed. The corn consumed out of the hoppers will be about one
bushel per hen. The beef scrap will also be less than with yarded
fowls, perhaps twenty-five cents per hen. Now, of the corn we will
raise on the land, at least ten acres. This should yield us five
hundred bushels. This leaves fifteen hundred bushels of corn to be
purchased. At the present high rates, this will cost $1,000 which,
added to beef scrap cost, makes an outside feed cost of $1,500. The
seed cost of rye, rape, cow-peas, etc., will amount to about $50 per
annum. For expense of production we have:
Interest and upkeep of plant $600.00
Purchased corn 1000.00
Beef scrap and grit 500.00
Team feed 100.00
This figures out the cost of production at a little more than a
dollar per hen. The income from the place should be about as
follows: Eleven hundred cockerels sold as squab broilers at 40 cents
each, $440.00; four hundred and seventy-five old hens at 30 cents,
The receipts from egg yield are, of course, impossible of very
accurate calculation, for it is here that the personal element that
determines success or failure enters. The Arkansas per-hen-day
figures (see last chapter), multiplied by the average quotation for
extras in the New York market, will be as fair as any, and certainly
cannot be considered a high estimate, as it is only 113 eggs per hen
Price per doz Income for
Eggs per Extras month from
hen day in New York 2000 layers
January .32 $ .30 $494.00
February .30 .29 404.00
March .62 .22 700.00
April .38 .19 350.00
May .44 .19 429.00
June .42 .18 377.00
July .34 .21 367.00
August .38 .22 429.00
September .21 .25 262.00
October .22 .28 316.00
November .18 .33 267.00
December .15 .32 246.00
The total income as figured will be $5,221. From this subtract the
cost of production, and we have still nearly $3,000, which is to be
combined item of wages and profit. We have entered no labor bill
because this is to be a one-man farm, and with the assistance of the
public hatchery and co-operative marketing association, which will
send a wagon right to a man's door to gather the eggs, it is
entirely feasible for one man to attend to two thousand hens. In the
rush spring season other members of the family will have to turn out
and help, or a man may be hired to attend the plowing and rougher
This is a good handsome income, and yet the above price of the man's
labor--it is only about one dollar per hen, which has always been
the estimated profit of successful poultry keeping. As a matter of
fact, this profit is seldom reached under the old system of poultry
keeping, not because the above gross income cannot be reached, but
because the expenses are greater. Under the present methods, with
the exception of the rearing of the young chicks, one man can easily
take care of three thousand hens. Indeed, practically the only work
in their care is cultivating the ground and hauling around and
dumping into hoppers, about two loads of feed per week.
But, young chicks must be reared, and this is more laborious. For
this reason I advise going into some other industry on a part of the
land, which will not require attention in the young chick season.
One of the best things for this purpose is the cultivation of cane
fruits as blackberries, raspberries and dewberries. The work of
caring for these can be made to fall wholly without the young chick
season. Peaches and grapes for a slower profit can be added, but
spraying and cultivation of these is more liable to take spring
labor. All these fruits have the advantage of doing well in the same
kind of soil recommended for chickens. Young chickens may be grown
around such berry crops and removed to permanent quarters before the
berries ripen. Strawberries would be a very poor crop because their
labor falls in the chick season.
Another plan, and perhaps a better one, is to have about three
fields, and rotate in such a manner that a marketable crop may be
always kept growing in the third field. Any crop may be selected,
the chief labor of which falls between July and the following March.
Late cabbage and potatoes, or celery, will do if the ground is
suitable for these crops. Kale and spinach are staple fall crops.
Fall lettuce could also be grown. If the market is glutted on such
crops, they can be fed out at home. Whenever a field is vacant, have
some crop growing on it, if only for purposes of green manuring.
Never let sandy ground lie fallow.
A modification of the above plans suited to heavier ground, is to
seed down the entire farm to grass. It is then divided into three
fields and provided with three sets of colony houses. Coops are
entirely dispensed with, and cheap indoor brooders are used in the
permanent houses. The pullets stay in these same houses in the same
field until the moulting season of the third year, or until they are
two and a half years old. One field will always be vacant during the
fall and winter season which time may be utilized for fresh seeding.
The difficulty of maintaining a sod will necessitate somewhat
heavier soil than by the previous plan. The houses should be moved
around occasionally, as the grass kills out in the locality. This
plan is a lazy man's way, taking the least labor of any method of
poultry keeping known. It is adapted to the cheaper ground in the
region farthest from market. On the Atlantic seaboard, the more
enterprising man will use the third field for rotation, and sell
some of the fertility of the western grain in the form of a truck
Five Acre Poultry Farms.
Can a living for a family be made from a five acre poultry farm?
Yes; by individual effort, where the marketing opportunities are
good; by corporate or co-operate effort, any place where the
fundamental conditions are right.
This type of poultry farm is well suited for development near our
large cities, where the cry of "back to the land" has filled with
new hope the discouraged dweller in flat and tenement. No greater
chance for humanitarian work, and at the same time no greater
business opportunity, is open to-day than that of the promotion of
colonies of small poultry and truck farms where the parent colony
not only sells the land, but helps the settler to establish himself
in the business and to successfully market the product. The natural
location for such projects is in the sandy soils of New Jersey,
Delaware, Maryland and Virginia.
We have already discussed the twenty-five acre farm, representing
the largest probable unit for such an enterprise. We will now
discuss the five acre farm which represents the smallest probable
On the five-acre farm a considerable difference of methods will be
necessary. In the first place, it is to be a horseless farm. All
hauling and plowing must be attended to by the central company, or
the same results could be obtained by a team owned in common by a
small group, say of six farmers, each of whom is to use the team one
day of the week.
A single isolated farmer in a community of farms or market
gardeners, could hire a team by the day as he needed it. I do not
recommend this scheme, however, but would suggest that the single
individual get a larger plot of ground, at least ten acres, and a
team of his own. In the co-operative community the five-acre
teamless farm is entirely feasible.
The tract should be surveyed about twice as long as wide, which, for
five acres, makes it 20 by 40 rods, or 330 by 660 feet. Measure off
a strip one hundred feet back from the road. Fence the remainder of
the tract. Now run a partition fence down the center until we have
come to within twelve rods of the back side. Here run a cross fence.
This gives us three yards of about one and one-half acres each. The
gates are arranged so that one passes through the three yards in a
Where the middle partition fence adjoins the front fence, a well is
driven. A water line is run down the partition fence to the rear
The plot around the house is set in permanent crops, such as
berries, fruit trees, asparagus, rhubarb, etc. Of the other three
yards, at least one is kept in growing marketable crops. Every inch
is cultivated, and crops of the leafy nature, as lettuce, cabbage,
kale and spinach, are chiefly grown, as they utilize the rich
nitrogenous poultry manure to the best advantage, and the waste
portions, or worthless crops, are utilized for the poultry. The
method of supplying the fowls with green food is entirely by
soiling. This means to grow the food in an adjoining lot and throw
it over the fence. The above mentioned crops are all good for the
purpose. Rape, which is not grown for human food, is also excellent.
Kale is one of the very best crops for soiling purposes. It is
planted in the fall and fed by pulling off the lower leaves during
the winter. In the spring the hardened stalks stand at a
considerable height and the field may be used for growing young
chicks, giving shade, and at the same time producing abundant green
feed, without any immediate labor, which means a great saving in the
A set of panels or netting stretched on light frames is provided.
They are of sufficient number to set along the longest side of one
of the fields. A strip along the fence, four or five feet wide, can
be planted to sunflowers, corn, rape, kale, or other rank growing
crop and the panels leaned against the fence to protect the young
plants from the hens. In this way the fence rows can be kept
provided with the shade of growing crops, which relieves the
otherwise serious fault of this plan of poultry farming, in that the
hens would be required to live in absolutely barren and sunburned
lots, for we propose to keep five or six hundred hens on one and a
half acres of ground, and no green things could get a start without
Rotate the houses from field to field as often as the crops allow.
Never permit hens to run in one bare field for more than six months
at a time. Always keep every inch of ground not in use by the
chickens, luxuriant in something green. If you have a crop of
vegetables which are about matured, drill rape or crimson clover
between the rows; by the time the crop is harvested and the hens are
to be moved in, such crops will have made a good growth. The hens
will kill it out but it will be a "profitable killing."
By this system of intensive combination of trucking and poultry
farming, we have a combination which for small capital and small
lands cannot be beaten. The hens should yield better than a dollar
profit per head on this plan; the one and a half acres automatically
fertilized and intensely cultivated, growing two or three crops a
year, should easily double the income.
Twelve hundred dollars a year is a conservative estimate for the net
income from such a plant, and the original investment, exclusive of
residence, will not be over one thousand dollars.
The differences in the process of reproduction in birds and mammals
is frequently misunderstood. The laying of the bird's egg is not
analogous to the birth of young in mammals.
The female, whether bird or beast, forms a true egg which must be
fertilized by the male sperm cell before the offspring can develop.
In the mammal, if fertilization does not occur, the egg which is
inconspicuous, passes out of the body and is lost. If fertilized, it
passes into the womb where the young develops through the embryonic
stages, being supplied with nourishment and oxygen directly by the
In the bird, the egg, fertilized or unfertilized, passes out of the
body and, being of conspicuous size, is readily observed. The size
of the egg is due to the supply of food material which is comparable
with that supplied to the mammalian young during its stay in the
The reptiles lay eggs that are left to develop outside of the body
of the mother, subject to the vicissitudes of the environment. The
young of the bird, being warm blooded, cannot develop without more
uniform temperature than weather conditions ordinarily supply. This
heat is supplied by the instinctive brooding habit of the mother
Fertility of Eggs
In a state of nature the number of eggs laid by wild fowl are only
as many as can be covered by the female. These are laid in the
spring of the year, and one copulation of the male bird is
sufficient to fertilize the entire clutch. Under domestication, the
hen lays quite indefinitely, and is served by the male at frequent
intervals. The fertilizing power of the male bird extends over a
period of about 15 days.
For most of my readers, it will be unnecessary to state that the
male has no influence upon the other offspring than those which he
actually fertilizes within this period. The belief in the influence
of the first male upon the later hatches by another male is simply a
The domestic chicken is decidedly polygamous. The common rule is one
male to 12 or 15 hens. I have had equally good results, however,
with one male to 20 hens. In the Little Compton and South Shore
districts, one male is used for thirty or even forty hens.
By infertile eggs is meant eggs in which the sperm cell has never
united with the ovum. Such eggs may occur in a flock from the
absence of the male, from his disinclination or physical inability
to serve the hens, from the weakness or lack of vitality in the
sperm cells, from his neglect of a particular hen, from
lifelessness, or lack of vitality in the ovule, or from chance
misses, by which some eggs fail to be reached by the sperm cells.
In practice, lack of sexual inclination in a vigorous looking
rooster is very rare indeed. The more likely explanation is that he
neglects some hens, or that the eggs are fertilized, but the germs
die before incubation begins, or in the early stages of that
process. The former trouble may be avoided by having a relay of
roosters and shutting each one up part of the time. The latter
difficulty will be diminished by setting the egg as fresh as
possible, meanwhile storing them in a cool place. The other factors
to be considered in getting fertile eggs, are so nearly synonymous
with the problems of health and vitality in laying stock generally,
that to discuss it here would be but a repetition of ideas.
In connection with the discussion of fertile eggs, I want to point
out the fact that the whole subject of fertility as distinct from
hatchability, is somewhat meaningless. The facts of the case are,
that whatever factors in the care of the stock will get a large
percentage fertile eggs, will also give hatchable eggs and vice
versa. This is to be explained by the fact that most of the
unfertile eggs tested out during incubation, are in reality dead
germs in which death has occurred before the chick became visible to
the naked eye. Such deaths should usually be ascribed to poor
parentage, but may be caused by wrong storage or incubation.
Likewise, it would not be just to credit all deaths after chicks
became visible to wrong incubation, although the most of the blame
probably belongs there.
Likewise, with brooder chicks, we must divide the credit of their
livability in an arbitrary fashion between parentage, incubation,
and care after hatching.
By the hatchability of eggs, we then mean the percentage of eggs set
that hatch chicks able to walk and eat. By the livability of chicks,
we mean the percentage of chicks hatched that live to the age of
four weeks, after which they are subject to no greater death rate
than adult chickens. By the livability of eggs, we mean the product
of these two factors, i.e.: the percentage of chicks at four weeks
of age based upon the total number of eggs set.
As before mentioned, the fertility of eggs bears fairly definite
relation to the hatchability, so likewise the hatchability bears a
relation to the livability of chicks. When poor hatches occur
because of weak germs, as because of faulty incubation, this same
injury to the chick's organism is carried over and causes a larger
death among the hatched chicks.
Moreover, the relation between the two is not the same with all
classes of hatches, but as hatches get poorer the mortality among
the chicks increases at an accelerating rate. The following table
gives a rough approximation of these ratios:
Per cent. of Per cent. of chick Per cent. of egg
Hatchability. Livability. Livability.
100 100 100
90 95 85
80 88 70
70 84 50
60 72 43
50 55 27
40 40 16
30 24 7
20 10 2
10 2 1
These figures are based on incubator data. Eggs set under hens
usually give a hatchability of 50 per cent. to 65 per cent., and
livability of 70 per cent. to 80 per cent. The reason for the
greater livability is that the real hatchability of the eggs is 70
per cent. to 75 per cent., and is reduced by mechanical breakage.
The hatchability of eggs varies with the season. This variation is
commonly ascribed to nature, it being stated that springtime is the
natural breeding season, and therefore eggs are of greater
While there may be a little foundation for this idea, the chief
cause is to be found in the manner of artificial incubation, as will
be discussed in a later section of this chapter. The following table
is given as the seasonable hatchability for northern states. This is
based on May hatch of 50 per cent:
January 38 July 40
February 42 August 40
March 47 September 42
April 49 October 43
May 50 November 40
June 46 December 35
Most people have an exaggerated idea of the hen's success as a
hatcher. I have a number of records of hen hatching with large
numbers of eggs set, and they are all between 55 per cent. and 60
per cent. The reasons the hen does not hatch better are as follows:
First: Actual infertile eggs--usually, running about 10 per cent. in
the best season of the year.
Second: Mechanical breakage.
Third: Eggs accidentally getting chilled by rolled to one side of
the nests, or by the sick, lousy or crazy hens leaving the nests or
standing up on the eggs.
Fourth: Eggs getting damp from wet nests, dung or broken eggs; thus
causing bacterial infection and decay.
The last three causes are not present in artificial incubation. From
my observation they cause a loss of 15 per cent. of the eggs that
fail to hatch, when hens are managed in large numbers. This would
properly credit our hens with hatches running from 70 per cent. to
75 per cent., which, for reasons later explained, is not equal to
hatches under the best known conditions of artificial incubation.
The assumption that the hen is a perfect hatcher, even barring
accidents and the inherited imperfection of the egg, is not, I
think, in harmony with our general conception of nature. Not only
are eggs under the hens subject to unfavorable weather conditions,
but the hen, to satisfy her whims or hunger, frequently remains too
long away from the eggs, allowing them to become chilled.
For directions of how to manage setting hens, consult the Chapter on
"Poultry on the General Farm."
The Wisdom of the Egyptians.
Up to the present there have been just three types of artificial
incubation that have proven successful enough to warrant our
attention. These are:
First, the modern wooden-box-kerosene-lamp incubator which is seen
at its best development in the United States.
Second, the Egyptian incubator of ancient origin, which is a large
clay oven holding thousands of eggs and warmed by smouldering fires
Third, the Chinese incubator, much on the principle of the Egyptian
hatchery, but run in the room of an ordinary house, heated with
charcoal braziers and used only for duck eggs.
I have no accurate information on the results of the Chinese method,
and as it is not used for hen eggs, we will confine our attention to
the first two processes only.
I do not care to go into detail in discussing makes of box
incubators, but I will mention briefly the chief points in the
development of our present machines.
The first difficulties were in getting lamps, regulators, etc., that
would give a uniform temperature. This now has been worked out to a
point where, with any good incubator and an experienced operator,
the temperature of the egg chamber is readily kept within the
These are two principal types of box incubators now in use. In the
earliest of these, the eggs were heated by radiation from a tank of
hot water. These machines depended for ventilation or, what is much
more important, evaporation, upon chance air currents passing in and
out of augur holes in the ends or bottom of the machine.
The second, or more modern type, warms the eggs by a current of air
which passes around a lamp flue where, being made lighter by the
expansion due to heat, the air rises, creating a draft that forces
it into the egg chamber. There it is caused to spread by muslin or
felt diaphragms so that no perceptible current of air strikes the
eggs. This type is the most popular type of small incubator on the
market. Its advantage will be more readily seen after the discussion
of the principles of incubation.
Hazy tales of Egyptian incubators have gone the rounds of poultry
papers these many years. More recently some accurate accounts from
American travelers and European investigators have come to light,
and as a result, the average poultry editor is kept busy trying to
explain how such wonderful results can be obtained "in opposition to
the well-known laws of incubation."
The facts about Egyptian incubators are as follows: They have a
capacity of 50 to 100 thousand eggs, and are built as a single large
room, partly underground and made of clay reinforced with straw. The
walls are two or three feet thick. Inside, the main rooms are little
clay domes with two floors.
The hatching season begins the middle of January and lasts three
months. A couple of weeks before the hatching begins, the fireproof
house is filled with straw which is set afire, thoroughly warming
the hatchery. The ashes are then taken out and little fires built in
pots are set around the outside of the big room. The little clay
rooms with the double floors are now filled with eggs. That is, one
is filled at a time, the idea being to have fresh eggs entering and
chicks moving out in a regular order, so as not to cause radical
changes in the temperature of the hatchery.
No thermometer is used, but the operator has a very highly
cultivated sense of temperature, such as is possessed by a cheese
maker or dynamite dryer. About the twelfth day the eggs are moved to
the upper part of the little interior rooms where they are further
removed from the heated floor. The eggs are turned and tested out
much as in this country. They are never cooled and the room is full
of the fumes and smoke of burning straw. The ventilation provided is
This is about the whole story save for results. The incubator men
pay back three chicks for four eggs, and take their profits by
selling the extra chicks that are hatched above the 75 per cent.
This statement is in itself so astonishing and yet convincing, that
to add that the hatch runs between 85 per cent. and 90 per cent. of
all eggs set, and that the incubators of the Nile Delta hatch about
75,000,000 chicks a year seems almost superfluous. As for the
explanation of the results of the Egyptian incubators compared with
the American kerosene lamp type, I think it can best be brought
about by a consideration in detail of the scientific principles of
Principles of Incubation.
HEAT.--To keep animal life, once started, alive and growing, we
need: First, a suitable surrounding temperature. Second, a fairly
constant proportion of water in the body substance. Third, oxygen.
Now, a fertile egg is a living young animal and as such its wants
should be considered. We may at once dispose of the food problem of
the unhatched chick, by saying that the food is the contents of the
egg at the time of laying, and as far as incubation is concerned, is
beyond our control.
In consideration of external temperature in its relation to life, we
should note: (A) the optimum temperature; (B) the range of
temperature consistent with general good health; (C) the range at
which death occurs. Just to show the principle at stake, and without
looking up authorities, I will state these temperatures for a number
of animals. Of course you can dispute the accuracy of these figures,
but they will serve to illustrate our purpose:
External External External Internal Internal
Optimum Healthful Fatal Optimum Fatal
Point Range Range Point Range
Man 70 0 to 100 50 to 140 98 90 to 106
Dog 60 70 to 140 70 to 140 101 95 to 110
Monkey 90 30 to 140 30 to 140 101 95 to 108
Horse 80 20 to 120 20 to 120 99 95 to 105
Fowl 80 20 to 140 20 to 140 107 100 to 115
chick 90 70 to 100 40 to 120 108 100 to 115
at start of
incubation 103 32 to 110 31 to 125 103 31 to 125
three days 103 98 to 105 80 to 118 103 95 to 118
eighteen days 103 75 to 105 50 to 118 106 98 to 116
This table shows, among other things, that we are considering in the
chick not a new proposition to which the laws of general animal life
do not apply, but merely a young animal during the process of growth
to a point where its internal mechanism for heat control, has power
to maintain the body temperature through a greater range of external
In the cooling process that occurs after laying the living cells of
the egg become dormant, and like a hibernating animal, the actual
internal temperature can be subjected to a much greater range than
when the animal is active. After incubation begins and cell activity
returns, and especially after blood forms and circulation commences,
the temperature of the chick becomes subject to about the same
internal range as with other warm blooded animals.
In the case of fully formed animals, the internal temperature is
regulated by a double process. If the external temperature be
lowered, more food substance is combined with oxygen to keep up the
warmth of the body, while, if the external temperature be raised,
the body temperature is kept low by the cooling effects of
evaporation. This occurs in mammals chiefly by sweating. Birds do
not sweat, but the same effect is brought about by increased
breathing. Now, the chick gradually develops the heat producing
function during incubation, until towards the close of the period it
can take care of itself fairly well in case of lowered external
temperature. The power to cool the body by breathing is not,
however, granted to the unhatched chick, and for this reason the
incubating egg cannot stand excess of heat as well as lack of it.
The practical points to be remembered from the above are:
First: Before incubation begins, eggs may be subjected to any
temperature that will not physically or chemically injure the
Second: During the first few days of the hatch, eggs have no
appreciable power of heat formation and the external temperature for
any considerable period of time can safely vary only within the
range of temperature at which the physiological process may be
Third: As the chick develops it needs less careful guarding against
cooling, and must still be guarded against over-heating.
Fourth: It should be remembered, however, that eggs are very poor
conductors of heat, and if the temperature change is not great
several hours of exposure are required to bring the egg to the new
Temperature is the most readily observed feature about natural
incubation and its control was consequently the first and chief
effort of the early incubator inventors.
A great deal of experimental work has been done to determine the
degree of temperature for eggs during incubation. The temperature of
the hen's blood is about 105 to 107 degrees F. The eggs are not
warmed quite to this temperature, the amount by which they fail to
reach the temperature of the hen's body depending, of course, upon
the surrounding temperature. 103 degrees F. is the temperature that
has been generally agreed upon by incubator manufacturers. Some of
these advise running 102 degrees the first week, 103 degrees the
second, 104 degrees the third. As a matter of fact it is very
difficult to determine the actual temperature of the egg in the box
incubator. This is because the source of heat is above the eggs and
the air temperature changes rapidly as the thermometer is raised or
lowered through the egg chamber. The advice to place the bulb of the
thermometer against the live egg is very good, but in practice quite
variable results will be found on different eggs and different parts
of the machine.
With incubators of the same make, and in all appearances identical,
quite marked variation in hatching capacity has been observed in
individual machines. Careful experimentation will usually show this
to be a matter of the way the thermometer is hung in relation to the
heating surfaces and to the eggs. Ovi-thermometers, which consists
of a thermometer enclosed in the celluloid imitation of an egg, are
now in the market and are perhaps as safe as anything that can be
As was indicated in the previous section greater care in temperature
of the egg is necessary in the first half of the hatch. The
temperature of 102 degrees F. as above given is, in the writer's
opinion, too low for this portion of the hatch. An actual
temperature of 104 degrees at the top of the eggs will, as has been
shown by careful experimental work, give better hatches than the
Moisture and Evaporation.
The subject of the water content of the egg and its relation to
life, is the least understood of poultry problems.
The whole study of the water content of the egg during incubation
hangs on the amount of evaporation. Now, the rates of evaporation
from any moist object is determined by two factors: vapor pressure
and the rate of movement of the air past the object. As incubation
is always carried on at the same temperature, the evaporating power
of the air is directly proportioned to the difference in the vapor
pressure of water at that temperature, and the vapor pressure of the
air as it enters the machine. Thus, in order to know the evaporative
power of the air, we have only to determine the vapor pressure of
the air and to remember that the rate of evaporation is in
proportion to this pressure, i.e.: when the vapor pressure is high
the evaporation will be slow and the eggs remain too wet, and when
the vapor pressure is low the eggs will be excessively dried out.
The reader is probably more familiar with the term relative humidity
than the term vapor pressure, but as the actual significance of
relative humidity is changed at every change in outside temperature,
the use of this term for expressing the evaporating power of the air
has led to no end of confusion.
The influence of air currents on evaporation is to increase it
directly proportional with the rate of air movement. Thus, 10 cubic
feet of air per hour passing through an egg chamber would remove
twice as much moisture as would 5 cubic feet.
If the percentage of water in any living body be changed a
relatively small amount, serious disturbances of the physiological
processes and ultimately death will result. The mature animal can,
by drinking, take considerable excess of water without danger, for
the surplus will be speedily removed by perspiration and by the
secretion from the kidneys. But the percentage of water in the
actual tissues of the body can vary only within a narrow range of
not more than three or four per cent. The chick in the shell is not
provided with means of increasing its water content by drinking or
diminishing it by excretion, but the fresh egg is provided with more
moisture than the hatched chick will require, and the surplus is
gradually lost by evaporation. This places the water content of the
chick's body at the mercies of the evaporating power of the air that
surrounds the egg during incubation.
To assume that these risks of uncertain rates of evaporation is
desirable, is as absurd as to assume that the risks of rainfall are
desirable for plant life. As the plants of a certain climate have
become adapted to the amount of soil moisture which the climate is
likely to provide, so the egg has by natural selection been formed
with about as much excess of water as will be lost in an average
season under the natural conditions of incubation. Plant life
suffers in drought or flood, and likewise bird life suffers in
seasons of abnormal evaporative conditions. This view is
substantiated by the fact that the eggs of water fowl which are in
nature incubated in damper places, have a lower water content than
the eggs of land birds.
The per cent. of water contained in the contents of fresh eggs is
about 74 per cent., or about 65.5 per cent, based on the weight,
shell included. Unfortunately no investigations have been made
concerning the per cent. of water present in the newly hatched
Upon the subject of the loss of water for the whole period of
incubation, valuable data has been collected at the Utah, Oregon and
Ontario Experiment Stations.
In these tests we find that as a rule the evaporation of eggs under
hens is less than in incubators. With both hens and incubators, the
rate of evaporation is greatest at the Utah Station, which one would
naturally expect from the climate. The eggs under hens at the
Ontario Station averaged about 12 per cent. loss in weight, and
those at the Utah Station about 15 per cent. At both stations,
incubators without moisture ran several per cent. higher evaporation
than eggs under hens. The conclusions at all stations were that the
addition of moisture to incubators was a material aid to good
hatches of livable chicks.
At Ontario the average evaporation ran from as low as 7 per cent. At
Utah it reached as high as 24 per cent. Now as the entire loss of
weight is loss of water, the solid contents remaining the same, and
as the original per cent, of water contained in the egg (shell
included) is only 65.5, the chicks of the two lots with the same
amount of solid substance would contain water in the proportion of
58.5 to 41.5. Based on the weight of the chick, this would make a
difference of water content of over 25 per cent.
That human beings or other animals could not exist with such
differences in the chemical composition of the body, is at once
apparent. In fact I do not believe that the chick can live under
such remarkable circumstances. As I have picked the extreme cases in
the series given, it is possible that these extremes were
experimental errors, and as in the Utah data, no information is
given as what happened to the chicks, I have no proof that they did
live. But from the large number of hatches that were recorded below
9 per cent, and above 15 per cent., giving a variation of the actual
water content in the chick's body of about 10 per cent., it is
evident that chicks do hatch under remarkable physiological
difficulties. One explanation that suggests itself is, that as there
is considerable variation in evaporation of individual eggs due to
the amount of shell porosity, and the chicks that hatch in either
case may be the ones whose individual variations threw them nearer
By a further study from the Ontario data of the relation of the
evaporation to the results in livable chicks, it can be readily
observed that all good hatches have evaporation centering around the
12 per cent. moisture loss, and that all lots with evaporations
above 15 per cent. hatch out extremely poor.
The general averages of the machines supplied with some form of
moisture was 35 per cent. of all eggs set, in chicks alive at four
weeks of age, while the machines ran dry gave only 20 per cent. of
live chicks at a similar period.
Now, I wish to call attention to a further point in connection with
evaporation. If the final measure of the loss of weight by
evaporation were the only criterion of correct conditions of
moisture in the chick's body, the hatches that show 12 per cent., or
whatever the correct amount of evaporation may be, should be
decidedly superior to those on either side. That they are better,
has already been shown. But they are far from what they should be.
An explanation is not hard to find. The correct content of moisture
is not the only essential to the chick's well being at the moments
of hatching, but during the whole period of incubation. Under our
present system of incubation, the chick is immediately subject to
the changing evaporation of American weather conditions. The data
for that fact, picked at random, will be of interest. The following
table gives the vapor pressure at Buffalo, N. Y., for twenty
consecutive days in April:
Supposing a hatch to be started at the beginning of the above
period, by the end of the first week, with the excessive
evaporation, due to a low vapor pressure, the eggs would all be
several per cent. below the normal water content; the fact that the
next week was warm and rainy, and the vapor pressure rose until the
loss was entirely counterbalanced, would not repair the injury, even
though the eggs showed at the end of incubation exactly the correct
amount of shrinkage. A man might thirst in the desert for a week,
then, coming to a hole of water fall in and drown, but we would
hardly accept the report of a normal water content found at the
post-mortem examination as evidence that his death was not connected
with the moisture problem.
The change of evaporation, due to weather conditions, is, under
hens, less marked than in incubators. This is because there are no
drafts under the hen, and because the hen's moist body and the moist
earth, if she sets on the ground, are separate sources of moisture
which the changing humidity of the atmosphere does not affect. Among
about forty hens set at different times at the Utah Station and the
loss of moisture of which was determined at three equal periods of
six days each, the greatest irregularity I found was as follows: 1st
period, 5.81 per cent; 2d period, 3.86 per cent; 3d period, 6.15 per
cent. Compare this with a similar incubator record at the same
station in which the loss for the three periods was 5.63, 9.18 and
I think the reader is now in position to appreciate the almost
unsurmountable difficulties in the proper control of evaporation
with the common small incubator in our climate. It is little wonder
that one of our best incubator manufacturers, after studying the
proposition for some time, threw over the whole moisture
proposition, and put out a machine in which drafts of air were
slowed down by felt diaphragms and the use of moisture was strictly
The moisture problem to the small incubator operator presents itself
as follows: If left to the mercies of chance and the weather, the
too great or too little evaporation from his eggs will yield hatches
that will prove unprofitable. In order to regulate this evaporation,
he must know and be able to control both vapor pressure and the
currents of air that strike the eggs. Now he does not know the
amount of vapor pressure and has no way of finding it out. The
so-called humidity gauges on the market are practically worthless,
and even were the readings on relative humidity accurately
determined, they would be wholly confusing, for their effect of the
same relative humidity on the evaporation will vary widely with
variations of the out-of-door temperature.
If the operator knows or guesses that the humidity is too low, he
can increase it by adding water to the room, or the egg chamber, but
he cannot tell when he has too much, nor can he reduce the vapor
pressure of the air on rainy days when nature gives him too much
water. As to air currents he is little better off--he has no way to
tell accurately as to the behavior of air in the egg chamber and
changes in temperature of the heater or if the outside air will
throw these currents all off, since they depend upon the draft
Taking it all in all, the man with the small incubator had better
follow the manufacturer's directions and trust to luck.
The writer has long been of the conviction that a plan which would
keep the rate of evaporation within as narrow bounds as we now keep
the temperature, would not only solve the problem of artificial
incubation, but improve on nature and increase not only the numbers
but the vitality or livability of the chicks. With a view of
studying further the relations between the conditions of atmospheric
vapor pressure, and the success of artificial incubation, I have
investigated climatic reports and hatching records in the various
sections of the world.
The following are averages of the monthly vapor pressures at four
points in which we are interested:
Buffalo, St. Louis, San Fran- Cairo
Month N.Y. Mo. cisco. Egypt
January 87 98 311 279
February 81 94 310 288
March 138 224 337 287
April 171 283 332 311
May 301 423 317 328
June 466 550 345 365
July 546 599 374 413
August 496 627 382 435
September 429 506 389 372
October 285 327 342 365
November 271 225 285 321
December 143 133 243 397
A study of the extent of daily variations is also of interest. As a
general thing they are less extreme in localities when the seasonal
variations are also less. In Cairo, however, which has a seasonal
variation greater than San Francisco, the daily variations during
the hatching season are much less than in California. This is due to
a constant wind from sea to land, and an absolute absence of
rainfall, conditions for which Egypt is noted.
Nearness to a coast does not mean uniform vapor pressure, for with
wind alternating from sea to land, it means just the opposite.
As will be readily seen the months in spring which give the best
hatches, occupy a medium place in the humidity scale. The fact that
both hens and machines succeed best in this period, is to me very
suggestive of the possibility that with an incubator absolutely
controlling evaporation, much of the seasonal variation in the
hatchability would disappear.
The uniform humidity of the California coast is shown in the above
table. This is not inconsistent with the excellent results obtained
The Egyptian hatcher in his long experience has learned just about
how much airholes and smudge fire are necessary to get results. With
these kept constant and the atmosphere constant, we have more nearly
perfect conditions of incubation than are to be found anywhere else
in the world, and I do not except the natural methods. The climatic
conditions of Egypt cannot be equaled in any other climate, but as
will be shown in the last section of this chapter, their effect can
be duplicated readily enough by modern science and engineering.
Mr. Edward Brown, who was sent over here by the English Government
to investigate our poultry industry, was greatly surprised at our
poor results in artificial incubation. Compared with our
acknowledged records of less than 50 per cent. hatches, he quotes
the results obtained in hatching 18,000 eggs at an English
experiment station as 62 per cent. I have not obtained any data of
English humidity, but it is undoubtedly more uniform than the
eastern United States.
The last of the four life requisites we have to consider is that of
oxygen. The chick in the shell, like a fish, breathes oxygen which
is dissolved in a liquid. A special breathing organ is developed for
the chick during its embryonic stages and floats in the white and
absorbs the oxygen and gives off carbon dioxide. The amount of this
breathing that occurs in the chick is at first insignificant, but
increases with development. At no time, however, is it anywhere
equal to that of the hatched chicks, for the physiological function
to be maintained by the unhatched chicks requires little energy and
Upon the subject of ventilation in general, a great misunderstanding
exists. Be it far from me to say anything that will cause either my
readers or his chickens to sleep less in the fresh air, yet for the
love of truth and for the simplification of the problem of
incubation, the real facts about ventilation must be given.
In breathing, oxygen is absorbed and carbon dioxide and water vapor
are given off. It is popularly held that abundance of fresh air is
necessary to supply the oxygen for breathing and that carbon dioxide
is a poison. Both are mistakes. The amount of oxygen normally in the
air is about 20 per cent. Of carbon dioxide there is normally three
hundredths of one per cent. During breathing these gasses are
exchanged in about equal volume. A doubling or tripling of carbon
dioxide was formerly thought to be "very dangerous." Now, if the
carbon dioxide were increased 100 times, we would have only three
per cent., and have seventeen per cent. of oxygen remaining. This
oxygen would still be of sufficient pressure to readily pass into
the blood. We might breathe a little faster to make up for the
lessened oxygen pressure. In fact such a condition of the air would
not be unlike the effects of higher altitudes.
Some investigations recently conducted at the U.S. Experiment
Station for human nutrition, have shown the utter misconception of
the old idea of ventilation. The respiratory calorimeter is an
air-tight compartment in which men are confined for a week or more
at a time while studies are being made concerning heat and energy
yielded by food products. It being inconvenient to analyze such an
immense volume of air as would be necessary to keep the room
freshened according to conventional ventilation standards,
experiments were made to see how vitiated the air could be made
without causing ill effects to the subject.
This led to a remarkable series of experiments in which it was
repeatedly demonstrated that a man could live and work for a week at
a time without experiencing any ill effects whatever in an
atmosphere of his own breath containing as high as 1.86 per cent. of
carbon dioxide, or, in other words, the air had its impurity
increased 62 times. This agrees with what every chemist and
physiologist has long known, and that is that carbon dioxide is not
poisonous, but is a harmless dilutant just as nitrogen. This does
not mean that a man or animal may not die of suffocation, but that
these are smothered, as they are drowned, by a real absence of
oxygen, not poisoned by a fraction of 1 per cent. of carbon dioxide.
In the same series of experiments, search was made for the
mysterious poisons of the breath which many who had learned of the
actual harmlessness of carbon dioxide alleged to be the cause of the
ill effects attributed to foul air. Without discussion, I will say
that the investigators failed to find such poisons, but concluded
that the sense of suffocation in an unventilated room is due not to
carbon dioxide or other "poisonous" respiratory products, but is
wholly due to warmth, water vapor, and the unpleasant odors given
off by the body.
The subject of ventilation has always been a bone of contention in
incubator discussions. With its little understood real importance,
as shown in the previous section, and the greatly exaggerated
popular notions of the importance of oxygen and imagined poisonous
qualities of carbon dioxide, the confusion in the subject should
cause little wonder.
A few years ago some one with an investigating mind decided to see
if incubators were properly ventilated, and proceeded to make carbon
dioxide determinations of the air under a hen and in an incubator.
The air under the hen was found to contain the most of the obnoxious
gas. Now, this information was disconcerting, for the hen had always
been considered the source of all incubator wisdom. Clearly the
perfection of the hen or the conception of pure air must be
sacrificed. Chemistry here came to the rescue, and said that carbon
dioxide mixed with water, formed an acid and acid would dissolve the
lime of an egg shell. Evidently the hen was sacrificing her own
health by breathing impure air in order to soften up the shells a
little so the chicks could get out. Since it could have been
demonstrated in a few hours in any laboratory, that carbon dioxide
in the quantities involved, has no perceptible effect upon egg
shells, it is with some apology that I mention that quite a deal of
good brains has been spent upon the subject by two experiment
stations. The data accumulated, of course, fails to prove the
theory, but it is interesting as further evidence of the
needlessness in the old fear of insufficient ventilation.
At the Ontario Station, the average amounts of carbon dioxide under
a large number of hens was .32 of one per cent., or about ten times
that of fresh air, or one-sixth of that which the man breathed so
happily in the respiratory calorimeter. With incubators, every
conceivable scheme was tried to change the amount of carbon dioxide.
In some, sour milk was placed which, in fermenting, gives off the
gas in question. Others were supplied with buttermilk, presumably to
familiarize the chickens with this article so they would recognize
it in the fattening rations. In other machines, lamp fumes were run
in, and to still others, pure carbon dioxide was supplied. The
percentage of the gas present varied in the machines from .06 to .58
of one per cent. The results, of course, vary as any run of hatches
would. The detailed discussion of the hatches and their relation to
the amount of carbon dioxide as given in Bulletin 160 of the Ontario
Station, would be unfortunately confusing to the novice, but would
make amusing reading for the old poultryman. Speaking of a
comparison of two hatches, the writer, on page 53 of the bulletin
says, "The increase in vitality of chicks from the combination of
the carbon dioxide and moisture over moisture only, amounting, as it
does, to 4.5 per cent. of the eggs set, seems directly due to the
higher carbon dioxide content." I cannot refrain from suggesting
that if my reader has two incubators, he might set up a Chinese
prayer machine in front of one and see if he cannot in like manner
demonstrate the efficacy of Heavenly supplications in the hatching
The practical bearing of the subject of ventilation in the small
incubator is almost wholly one of evaporation. The majority of such
machines are probably too much ventilated. In a large and properly
constructed hatchery, such as is discussed in the last section of
this chapter, the entire composition of the air, as well as its
movement, is entirely under control. Nothing has yet been brought to
light that indicates any particular attention need be given to the
composition of such air save in regard to its moisture content, but
as the control of this factor renders it necessary that the air be
in a closed circuit, and not open to all out-doors, it will be very
easy to subject the air to further changes such as the increasing
oxygen, if such can be demonstrated to be desirable.
The subject of turning eggs is another source of rather meaningless
controversy. Of course, the hen moves her eggs around and in doing
so turns them. Doubtless the reader, were he setting on a pile of
door knobs as big as his head, would do the same thing. As proof
that eggs need turning, we are referred to the fact that yolks stick
to the shell if the eggs are not turned. I have candled thousands of
eggs and have yet to see a yolk stuck to the shell unless the egg
contained foreign organism or was several months old. However, I
have seen hundreds of blood rings stuck to the shell. Whether the
chick died because the blood rings stuck or whether the blood rings
stuck because the chicken died I know not, but I have a strong
presumption that the latter explanation is correct, for I see no
reason if the live blood ring was in the habit of sticking to the
shell, why this would not occur in a few hours as well as in a few
In the year 1901 I saw plenty of chicks hatched out in Kansas in egg
cases, kitchen cupboards and other places where regular turning was
Mr. J.P. Collins, head of the Produce Department of Swift & Co.,
says that he was one time cruelly deserted in a Pullman smoker for
telling the same story. The statement is true, however, in spite of
Mr. Collins' unpleasant experience. Texas egg dealers frequently
find hatched chickens in cases of eggs.
Upon the subject of turning eggs the writer will admit that he is
doing what poultry writers as a class do on a great many occasions,
i.e.: expressing an opinion rather than giving the proven facts. In
incubation practice it is highly desirable to change the position of
eggs so that unevenness in temperature and evaporation will be
balanced. When doing this it is easier to turn the eggs than not to
turn them, and for this reason the writer has never gone to the
trouble of thoroughly investigating the matter. But it has been
abundantly proven that any particular pains in egg turning is a
waste of time.
The belief in the necessity of cooling eggs undoubtedly arose from
the effort to follow closely and blindly in the footsteps of the
hen. With this idea in mind the fact that the hen cooled her eggs
occasionally led us to discover a theory which proved such cooling
to be necessary. A more reasonable theory is that the hen cools the
eggs from necessity, not from choice. In some species of birds the
male relieves the female while the latter goes foraging.
But there is no need to argue the question. Eggs will hatch if
cooled according to custom, but that they will hatch as well or
better without the cooling is abundantly proven by the results in
Egyptian incubators where no cooling whatever is practiced.
Searching for the "Open Sesame" of Incubation.
The experiment station workers have, the last few years, gone a
hunting for the weak spot in artificial incubation. Some reference
to this work has already been made in the sections on moisture and
ventilation. Before leaving the subject I want to refer to two more
efforts to find this key to the mystery of incubation and in the one
case at least correct an erroneous impression that has been given
At the Ontario Station a patent disinfectant wash called "Zenoleum"
was incidentally used to deodorize incubators. Now, for some reason,
perhaps due to the belief that white diarrhoea was caused by a germ
in the egg, this idea of washing with Zenoleum was conceived to be a
possible solution of the incubator problem. In the numerous
experiments at that station in 1907 Zenoleum applied to the machine
in various ways was combined with various other incipient panaceas
and at the end of the season the results of the various combinations
were duly tabulated. The machine with buttermilk and Zenoleum headed
the list for livable chicks.
For reasons explained in the chapter on "Experiment Station Work,"
the idea of contrasting the results of one hatch with one sort with
the average results of many hatches of another sort is very poor
science. Feeling that the Station men would hardly be guilty of
expressing as they did in favor of such a method without better
reason, I very carefully went over the results and compared all
machines using Zenoleum with all machines without it. The results in
favor of Zenoleum were less marked but still perceptible. I was
somewhat puzzled, as I could see no rational explanation of the
relation between disinfecting incubator walls and the hatchability
of the chick in its germ-proof cage. Finally I hit upon the scheme
of arranging the hatches by dates and the explanation became at once
apparent. The hatching experiments had extended from March to July,
but the Zenoleum hatches were grouped in April and early in May,
when, as one would expect from weather conditions, all hatches were
running good. After allowing for this error Zenoleum appeared as
harmless and meaningless as would the Attar of Roses.
The second link after the missing link of incubation to which I wish
to call your attention also occurred at the Ontario Station. The
latter case, however, is happier in that no unwarranted conclusions
were drawn and that an interesting bit of scientific knowledge was
added to the world's store. The conception to be tested was an
offshoot from the carbon dioxide theory. You will remember at the
Utah Station the idea was that carbon dioxide was to dissolve the
shell so the chick could break out easier.
At the Guelph Station the conception was that the carbon dioxide
might dissolve the lime of the shell for the chick to use in "makin'
hisself." As an egg could not be analyzed fresh and then hatched, a
number were analyzed from the same hens and others from those hens
were then incubated with the various amounts of carbon dioxide,
buttermilk, Zenoleum, and other factors. The lime content of the
contents of the fresh egg averaged about .04 grams. At hatching time
the lime in the chick's body averaged about .20 grams and was always
several times as great as the maximum of the eggs.
Clearly calcium phosphate of the chick's bones is made by the
digestion of the calcium carbonate from the shell and its
combination with the phosphorus of the yolk. Certainly a remarkable
and hitherto unexplained fact. The amount of lime required is not
great enough, however, to materially weaken the shell, but, of
course, the process is vital to the chick as bones are quite
essential to his welfare, but it is an "inside affair" of which the
three-tenths of one per cent of carbon dioxide incidentally present
under the hen is entirely irrelevant.
A further observation made by the investigator is that the chicks
which obtained the lowest amount of lime were abnormally weak. As
long as we are powerless to aid the chick in digesting lime this
fact, like the other, belongs in the field of pure, rather than
applied science. I think that we are safe in saying that the
weakness caused the shortage of lime rather than vice versa; if the
writer remembers runts in other animals are usually a little short
of bone material.
The chemist of the station is to be given special credit for not
jumping at conclusions. In the summary of this work he states:
"There is apparently no connection between the amount of lime
absorbed by the chick and the amount of carbon dioxide present
The Box Type of Incubator In Actual Use.
Although the fact is not so advertised and frequently not recognized
even by the makers, the success of existing incubators is directly
proportional to the extent with which they control evaporation. In
order to show this I have only to call attention briefly to two or
three of the most successful types of incubators on the market.
Let me first repeat that evaporation increases with increased air
currents and with decreased vapor pressure. Now, the vapor pressure
undergoes all manner of changes with the passing of storm centers
and the changes of prevailing winds. But there is a general tendency
for vapor pressure to increase with increase in outside temperature.
Now, the movement of air in all common incubators depends upon the
draft principle and the greater the difference in machine
temperature and outside temperature the greater will be this draft.
Thus, we have two factors combining to cause variation in the rate
of evaporation. The tendency for the rate of airflow to vary is
diminished when a cellar is used for an incubator room, but the
cellar does not materially remedy the climatic variation in vapor
The general tendency of incubators as ordinarily constructed, is to
dry out the eggs too rapidly. With a view of counteracting this,
water is placed in pans in the egg room. A surface of water exposed
to quiet air does not evaporate as fast as one might think, as is
easily shown by the fact that air above rivers, lakes and even seas
is frequently far from the saturation point. The result of the
moisture pan with a given current of air is that the vapor pressure
is increased a definite amount, but by no means is it regulated or
made uniform. Inasmuch as too much shrinking is the most prevalent
fault in box incubators, the use of moisture is on the whole
beneficial, but in hot, murky weather, with less circulation and
higher outside vapor pressure, the moisture is overdone and the
operator condemns the system.
The subject not being clearly understood and no means being
available for vapor pressure determinations, the system results in
confusion and disputes. When the felt diaphragm machine was brought
into the market it was advertised as a no-moisture machine. The
result of the diaphragm is that of choking off air movement and