Is it okay to open a chicken incubator when you see a small crack?
No This is the point when the emerging chick needs all the help you should give it, that is, leave it to do its job. The temperature and humidity need to remain constant in the incubator while the chick works to emerge from the shell. Opening the lid of the incubator reduces both and also reduces its chances of being healthy. Let all the chicks emerge and get dry and fluffy before opening the lid, they do not need food or water at this point. They will survive on the nutrition they took from the yolk for at least 24 hours and much longer. Heat and humidity are all they really need now.
