It depends on the humidity when they are dry.
I wouldn't take any out while others are still hatching.
Thanks for the info!For me it depends on how many eggs I am hatching. I have over time followed various different schools of thought. Sometimes I would take them out once a certain number of hatched chicks was reached, sometimes based on how long most had been cheeping and running around fully hatched and awake, sometimes based on looks and how fluffed they were, sometimes only if I did not see any active egg hatching at the moment and I thought I could minimize the humidity loss if I did it quick, etc... When I did take them out, I took them all, no matter at what stage post-hatch they were. Well....not like a freshly hatched 10 minutes ago chick....but anyone who could stand is grabbed. They can finish drying and fluffing under the heat lamp.
They can go for at least 24 hours in the incubator after hatch, so almost always are going to be grabbed up by you before that long.