If you can fix mama and chicks a little place on the floor where they can have some privacy and she feels safe then thats what I would do. Once the chicks are about 3 days old she'll bring them out. But she will feel a whole lot better if she has some privacy from the rest of the flock while she is nesting and during hatch. And you'll need to mark your eggs if you think others may lay in her nest, that way you can take out the newest eggs so your hatch day won't be drawn out.