means maintaining conditions favorable for developing and hatching
Four factors are of
major importance in incubating eggs artificially: temperature,
ventilation, and turning.
has shown that the optimum incubator temperature is 100° F
when the relative
humidity is 60 percent, the air is 21 percent oxygen, 0.5
percent carbon dioxide, and air movement past the egg is at 12
cubic feet per minute.
should be maintained between 99° F and 101° F. The acceptable
range is 97° to 102° F. High mortality is seen if the
temperature drops below 96° F or rises above 103° F
for a number of hours. If the temperature stays at either extreme
for several days, the egg may not hatch. Overheating is more
critical than underheating. Running the incubator at 105°
F for 15 minutes will seriously affect the embryos.
humidity of the air within an incubator for the first 18
days should be 60 percent. During the last 3 days (the hatching
period) the relative humidity should be nearer 65 to 70 percent.
Too much moisture in the incubator prevents normal evaporation
and results in a decreased hatch, but excessive moisture is
seldom a problem in small incubators. Too little moisture may
cause the chick
to stick to the shell and be crippled at hatching time.
Turning the eggs
during the incubation period prevents the embryo
from migrating through the albumen and sticking to the shell
membrane. Chicken eggs should be turned three to five times
daily from the 2nd to the 18th day. Do not turn the eggs during
the last 3 days!
The best hatching
results are obtained with normal air, which usually contains
21 percent oxygen. It is difficult to provide too much oxygen,
but a deficiency is possible. It is possible to suffocate the
eggs and chicks in an air-tight container.