We always leave the babies with the mom. She will teach them things. Ours are free range so we always keep mom and babies in their own pen til the babies are about six weeks old, not because we are afraid of the flock but to give them a chance against predators, and it makes momma feel more secure. But especially if yours are in a pen they should be fine. One of our hens who hatched ONE chick this summer was devoted to her baby; even after we let them out to join the flock she would still lead her baby into a pen whenever she got the opportunity, so that's how we knew they get some security from that. Baby is about 13 or 14 weeks old now and she STILL hangs out with momma; they are cute together and nice to see momma teaching her baby everything she knows to stay safe as possible.