the
extent that they feel cold to the face or hands. The length of time to
bring this about varies with the age of the eggs and the temperature of
the room.
_Moisture._ A good deal of moisture is used in incubating duck eggs. It
is usual to begin to spray the eggs with water the next day after
testing. However, this may vary anywhere from the sixth to the tenth
day. They are sprayed quite thoroughly, some men using water enough so
that it runs out of the bottom of the machine. No particular care is
taken to see that the water used is warm. Ordinary water just as it
comes from the pipes is commonly used and is applied by means of a spray
nozzle attached to a hose. However, extremely cold water should not be
used for this purpose. This spraying is done once or twice a day as the
operator may think necessary until the eggs begin to hatch. In many
cases even then if the ducklings seem to be drying too fast after they
come out of the shell, or to be having difficulty to get out it is well
to open the machines and wet the eggs down thoroughly.
_Fertility._ The fertility varies with the season that is, with the
weather. At the beginning of the laying season when the weather is cold
the fertility usually runs rather low. This is likewise true at the end
of the laying season when the heat of summer sets in. During the
interval between these two times of low fertility there will usually be
one or more periods during which the fertility will go down and then
come back again. This seems to occur even though the weather remains
about the same and though there is no change in the method of feeding.
Fertility may be considered to be good when it runs about 85%. When the
fertility is running poor the hatching of the eggs left in the machines
after testing will usually be poor also.
_Hatching._ It takes longer as a rule from the time that the ducklings
pip the eggs until they hatch than it does with chicks. To retain the
moisture which is so necessary during hatching, the machines are usually
shut tightly and are not opened until the hatching is pretty well
completed unless it becomes necessary to add more moisture as indicated
above. The little ducklings should be left in the incubator until the
hatching is over and they are thoroughly dried off. As soon as the
hatching is completed, the ventilators in the machines are opened to
hasten the drying process. If the ducklings open their bills and pant
it is an indication that they are not getting enough ventilation and
thi