I have Freedom Rangers, and one of the hens is hatching chicks. I am inclined to watch her carefully and take the chicks if she doesn't take care of them, but I am afraid that she will hurt them while i'm not there.
Is she a first time broody? Is she with the other birds or separate? Is there something in her personality that inclined you to believe she won't be a good mother? There are benefits to letting a hen raise your chicks. The chicks are usually stronger, smarter, and more easily integrate into your flock, and you won't need supplemental heat for them. However, it is a good idea to keep an eye on momma at first to make sure she and babies are bonding properly. Free range broodies and chicks also run the risk of predators.