On the 18th day of incubation, you also need to increase the humidity in the
incubator to 65 to 70 percent. You may want to increase the ventilation —
refer to your incubator’s directions to see whether doing so is advised. Get
your brooder set up and warmed on the 20th day so you can transfer the
chicks to it (see Chapter 14 for more on brooders).
Eggs that were put in the incubator at the same time should hatch within
18 hours of each other (see the section “Knowing what to look for: Stages of
embryonic growth” later in this chapter for more on embryo growth). Chicks
struggle to get out of the egg, and it may take some time for a chick to fully
hatch. If a chick requires help hatching, it usually isn’t a strong, healthy chick.
When chicks start hatching, people get excited, and they want to open the incubator
and handle the chicks. Stop right there!Leave the chicks alone until they
are dry and fluffy. They’re fine in the incubator for a few hours while the others
hatch. Remove the dry fluffy ones every six hours and put them in the brooder.
Every time you open the incubator, you lower the temperature and humidity
and make it harder for those still hatching. If there are eggs left after 18 hours
from the time the first chick hatched, you can leave them for another 24 hours,
but after that, examine some of them for signs of pipping or just throw them out.