REARING FROM INCUBATORS 91 
the methods of working are practically the same. A study of the 
incubator will repay the time given, but a profound knowledge 
of its mechanism is not necessary to its successful working. 
If one gets hold of the principle that the oil and lamp are the 
sources of the heat supply, that the capsule regulates the quantity 
of the heat, and that the temperature must be kept steady within 
narrow limits, a person of ordinary intelligence can do all that is 
necessary. 
The eggs should be tested in a dark room, with the help of 
a testing lamp, on the evenings of the sixth and seventh days. 
With a large machine it is best to make two testings on con- 
secutive evenings, or the drawer may be kept open too long and 
the eggs become unduly chilled. Each egg put back into the 
drawer as fertile should be specially marked. The staler eggs 
may need re-testing on the evening of the fourteenth day, but 
this should not be necessary if all the eggs be of the same, or 
nearly the same, degree of freshness when first put in. 
As far as possible, the room in which the machine is running 
should be kept at an even temperature, but free ventilation should 
be given at all times. Fresh air is a necessity if the chicks are to 
hatch out strong. 
The eggs should be turned daily according to directions, but 
from the time when the first egg begins to chip in the incubator 
the machine should be closed and not opened again for twenty- 
four hours. During this time the temperature should be main- 
tained steadily at 104° F. The chickens may remain in the 
incubator for thirty-six hours, when they should be removed to a 
“brooder,”’ that is already prepared and heated to a temperature 
of 99° F. Great care should be taken to prevent them getting 
a chill. A basket lined with wool, flannel or soft dry grass should 
be used, and the birds should be covered up with a down quilt 
during the removal. Any crippled or weakly chickens should be 
destroyed at once. 
Brooders that are sold to accommodate 100 chickens are rarely 
suitable for more than half that number. Perhaps 60 is a 
maximum number for a 100 brooder, 
