If you loose humidity by opening the bator while eggs are pipped, you run a risk of causeing 'shrink wrapped" chicks. Chicks can stay in the bator for up to 3 days if you so wish. The yolk they absorbed keeps their belly full. However, just like every other detail, different people do things differently. Different people have different theories on what they believe is the right way to do it. You have to find what's comfortable for you and what works best for you and the chicks. My bator holds humidity well. While I would be reluctant to continuously open it during a hatch, I have no problem opening it every few hours to scoop 3 or 4 chicks out. Some people will not open a bator till the hatch is completely done. I hatched out 13/16 eggs two weeks ago, no issues from me scooping out chicks or assisting with two hatches. The three that didn't hatch died in shell with no pipping.I thought you were not supposed to open the bater if others have piped? I was worried I would hurt the other eggs if I got the chick out? This is my very first hatching so I have a lot to learn. Is it ok to leave him in the bater overnight ?