I had expected that by now you'd have a heap of posts saying 'Yes - they'll peck them to death. separate them NOW'.
We free range and when our maternity unit (for four hens & chicks) is full the other hens just have to make do with the main coop (or outside the coop sometimes!). The ones in the maternity unit are separated from other chickens, but not from each other and the broody hen don't peck each others chicks.
The ones who are forced to hatch in the main coop also do not experience pecking from other hens or cockerels, the main problem with having them brood in the main coop is that the young cockerels sometimes bother them on the nest. After hatching though a mother with chicks is not to be messed with !
We have Japanese Bantams, that might make a difference. Other breeds are perhaps not so tolerant.