Foster Mother Hens?

I have two "fighting chicken" hens who hatched eggs about one week apart. One family was in a tiny pen, so we put both families together in a large, safe area. But the ladies did NOT get along. After separating them again, one of the moms kept trying to escape and rejoin the flock. She kept calling her chicks and they were going crazy! If we just let her leave, can we put her chicks in with the others, or will the second hen treat them badly? Or should I just wait until the hens decide that they are through with mothering? Right now, the chicks are two and three weeks old.

2-3 weeks is around when a mother decides she wants to teach her chicks how to be flock members. My broody Leghorn and my broody bantam cross both really wanted out of their large pen by then, even though it had almost everything they could want. They just start getting bored. I usually start letting them out around then. I didn't with my bantam and she escaped, abandoning her chicks. They were fully feathered, so thankfully they were okay without her. Our other broody, a kind silkie, was willing to partially adopt them, but this is pretty rare. I would think the other mother would probably attack them, and you should just give them a warm place to sleep on their own. They will learn to perch, forage, feed, and be a part of the flock on their own.
You could just let one broody out and keep the other locked up, or try letting them out together. I had two broodies out together, and one killed all three of the others chicks.

I hope this helps. And I hope all your birds stay healthy and happy. Best of luck!

Thanks for your advice. We've done our best to keep these little ones safe from at least 3 neighborhood hawks (red shoulder, red tail, & kestrel) and a family of crows, that it would be awful for them to be "done in" by their own species.