I hear alot of people that say leave them in there for 24 hours or till the other eggs hatch. I am shure someone will know more then I and answer you soon . Good luck
24 hours is perfectly safe for them(they hatch with part of the yolk still inside their bodies and the mother hens stay on the nest for a day or two after the eggs have hatched too..). It is not recommended to take the chicks out less than 12 hours after hatching. Especially chicks that are still unable to stand up and walk well. They also need to dry out or they run the risk of getting chilled. If the chicks have not fluffed out well(AFTER 12 hours at least!), just take a tissue and rub them all over and they will fluff out. This is sometimes necessary in hatches in incubator with only a few chicks, the down gets fluffed out naturally under hens by rubbing against her, nest mates and her feathers. In an incubator, chicks can get fluffed out well if there are a lot of chicks to bump up against. Even if the chicks seem fluffed out in less than 12 hours, they may not be completely dried out.. just leave them in there despite the temptation- it's best for them.