the other hens will still lay in there. just leave her marked ones and TAKE OUT THE REST! sorry I shouted at you. It is important because if you let too many hens lay and have too many eggs not all will hatch and it will just get gross. I don't like to move a broody. If she has a place to set and other hens have access it is okay, just be ready on hatch day to move her then. what I do on hatch day, is take out the ones that hatch and raise them in a cardboard box for a day, so other hens don't eat them, and it gives the others a chance to hatch., make sure they eat and drink. let mom hatch the rest, you can slip her an egg or two to keep her sitting. when they are all hatched put her in a separate pen till the chicks can fend for themselves against, hens,crows, cats and what not. atleast 6 weeks.