I believe she will keep them warm. I think you are safe to wait until they are all hatched, before taking them. They don't usually eat the first couple days, as they have nutrition from the yolk they absorbed. I have no experience with chicks hatched from a broody, but my new hatches usually sleep most of the first 24 - 48 hours. It's kinda like I can tell when the yolk nutrition is gone .... then they scurry about, eating, drinking, and pooping!
Good luck!
Good luck!
