Blood on the Dance Floor!

I have my mother and chick seperated from the rest of the girls but the door seperating has gaps in it. Last week I found blood all over the mum and around the gap separating the two. This week I have been trying in intergrate the Mum & chick with the rest. I have just found Mum fighting with the head Hen. They were both pretty exausted but neither were yielding. The other hen has no combe (leghorn I think) and she was going for the combe every time. In the end I separated the two and isolated Mum and chick completly.

What's my next move? Should I let them fight it out? They used to get on fine before the chick arrived. The chick is nearly four weeks old now.