She might accept chicks but her internal clock might tell her she is off by a few days.
I keep my hens and chicks separate from the other chickens. Other hens might kill the newborn chicks. When they get their first feathers, I will let the Mother hen out with her chicks but I keep a eye on...
Depends.
How long as she been broody? is there anything under her? (golfballs)
I just put 7 chicks under a Broody without a problem but she had been broody for awhile and was sitting on golfballs.
I put the chicks under her at night and watched to make sure she accepted them.