Think you just have to see. I have never had problems. I let my broody hens hatch out eggs quite often as I can sell the 'fancy bantams' easily and it help towards chicken food costs!i've been wondering if its alright to keep a hen and chicks in a coop with other chickens. is that alright? or do i need to seperate them?
Sometimes even 2 hens will share the same nest and both look after the chicks.
Maybe it depends of the breed of chicken.
Mine are Japanese Bantams. I have many roosters, hens and chicks or different sizes all living together well. The key is space. If they have a large run and plenty and stuff the hens and chicks can hide behind etc then there should not be a problem.
Normally a hen with chicks turns into a very frightening bird to her flock mates and will see off any other hen or rooster that she thinks is getting too close to her chicks.
I let my hens nest, hatch and rear the chicks all together in the same enclosure. I don't think it would work if I took away the broody and re introduced her later after the chicks hatched.