I leave mine with the flock whenever possible. If there's enough space, everyone should be fine. No one will mess with the momma hen! As the chicks get older the mature hens will teach them manners, they'll get a peck to the head every once in a while, make a huge fuss and run back to momma. Momma will basically say "what did you expect, you were in her way" and be fine with that. Chick will learn to respect the elder members of the flock and all will be fine. No problems integrating everyone later, and the chicks learn to be good flock members from the start.
I've never had a bird kill a broody's chick. Only problem I've had was 2 broodies hatch at the same time, the alpha tried to kill the beta's chicks. IME, the rooster is not aggressive to the chicks (I would cull any rooster that attacked chicks), but helps the broody momma maintain peace in the flock and actually babysits sometimes if the chick gets separated from momma.
I'm with George, watching a momma chick raise her babies should be on everyone's bucket list. You'll learn a lot about raising chicks, flock manners, and just get so much enjoyment from watching them. Plan to cancel your cable, you won't be watching any tv anymore lol!