Helping chicks hatch out

[Rowsdower]

My sister is a preschool teacher and is currently hatching about 20 eggs in her classroom 'bator. Hatch day is technically tomorrow. She came into the class this morning to find that 6 of them had pipped (she last checked them on Saturday so there's no telling when they actually started). After several hours, they have sort of stalled a bit in their hatching. Some of them have holes big enough to poke their heads through. She'll be leaving the school for the evening shortly and is terrified that if she leaves them that the membranes might dry out and entrap them. Any thoughts? Should she go ahead and free the little buggers?

 

[Rowsdower]

I just wanted to add that this is the first year using this incubator and she says that she doesn't see nearly as much condensation in the 'bator as last year. But apparently she doesn't have a proper hygrometer to measure the specific humidity. This is why she's so scared that the membranes will dry.