After a chick cracks the shell how long will it take for it to hatch?

This first opening of a hole in the shell is called peeping and happens on day 21. Most chicks take anywhere from 1 hour up to 24 hours to complete the task. The humidity in the incubator must be very high (85%) to allow moisture between the chick and the inner shell. Leave the peeped chicks in the incubator until they are fluffy and moving around, this also encourages the un-peeped chicks to finish emerging.