Burlington weekly free press. [volume] (Burlington, Vt.) 1866-1928, 1919-03-13

is almost as necessary as turning them.
1t not only exposes the eggs to fresh
air. but cooling causes the contents to
contract, and thereby draw through tho
pores of the shell a fresh supply Of oxyI
gen. Cooling the eggs means chicks of
strong vitality, whereas lack Of coolingl
often produces weak chicks which are !
hard to rear in the brooder.
No fxed rules can be given for the |
required amount of cooling. Much de-
Ponds upon the season of the year, the |
temperature of the incubator cellar and
the temperature at which the hatch has [
run for the preceding "a hours. During /
the first week of incubation it is likely |
that sufficient cooling will be obtained
i'll turning the eggs After the seventh
day leave the trays on top of the ma
chine or on tables until the eggs, when
placed against the cheek, feel neither
warm nor cold. From Is minutes to a.
half hour Is about the correct time.
1t is customary to cool the eggs att
the morning turning, not at the evening
turning, too. unless the hatch is pretty
well advanced and the weather is ex-l
| ceedinsly warm, in which case two cool
| ngs of slight duration will sometimes,
prove of more value than a single long
er cooling. Common sense is the deter
! mining factor in most of these operations.
I If the temperature of the egg chamber
| before turning was little high, the eggs
can stand more cooling; if the heat was
| a trife low. the eggs should receive less
| cooling.
AS the hatch advances especially after
| the second week. the embryos give off
| considerable heat Of their own, conse-
! quently it is usually necessary to re-
| duce the heat from the lamp by turning
| the flame lower. Toward the close of II
| hatch on very warm days it is sometimes
necessary to turn out the lamp entirely
for several hours at a stretch. to pre-
vent overheatng the eggs.
ON THE EIGHTEENTH DAY
On the evening of the 18th day of in
| cubation the eggs should be turned and
| cooled for the last time, and the ma
| chine kept closed until the hatch Is
completed or we'll along. By this time the
chick is almost fully developed. and hav-
ing reached this stage it takes up the
position that will best enable 1t to pip
the she'll The shells are usually pipped
on the evening of the 18th day or morn
ing Of the Goth day, and during the fol-
lowing "a hours the chicks emerge from
| the shells.
| Many incubator operators prefer to start
! a hatch al l02 degrees, and gradually
| allow 1t TO creep up to 1903 1-2 degrees
| by the 18th day. Others hold a temper
allure OF 1903 degrees for the entire pc
| riod. Immediately before the hatch Ia
due the temperature is likely to rise to
lo4 degrees. or even 1oi 1-2 degrees. which
is TO be expected; but try not to permit
the heat TO go above this level.
Fluctuations in temperature are likely
to occur even with the most careful
management-that is. the thermometer
! will register wide variations-but this
does not mean that the eggs have tho
same temperature. Bear in mind that
several hours are required to affect the
interior of the egg single degree Thus
If you suddenly find something wrong
with the heating apparatus and the Their
mometer registering 9s degrees or LOG
degrees. 1t does not follow necessarily
that the interior Of the eggs has reache ed
either extreme.
The operator should aim to preserve
a uniform temperature, of course, but
he need not worry If slight variations
occur. There Is considerable latitude or
reserve margin of safety, especially after
the first week, to carry the, eggs over
inequalities II this were not so the hen
would have great difficulty in bringing
off a successful hatch. since she is known
to leave her nest at odd times and for
unequal periods.
| 1t is customary TO test the eggs dur
ing incubation; in good practice they are
tested twice-first for fertility, on or
about the seventh day and again for
the strength of the embryos, about the
18th day, so that all dead eggs can be re-
moved This testing process is similar
TO Gambling market eggs, which is moth
ing more than holding the eggs before
a strong spot of light, preferably In a
darkened room. SO that the contents of
the eggs are made clearly visible through
the shell. 1t is a simple operation and
wilt be explained in detail in a succeed
ing article
5 Copyright 1919. by Public Ledger Coz