Most mother hens wait until they hear the kids peeping loudly to go look for them. Otherwise they seem to assume everything is well. Glad she's doing well.
I generally wait until chicks are around 2 weeks of age. Than they are strong enough to get away. If necessary I would pen the aggressive hen until the chicks get bigger. I've had hens kill chicks so I would definitely take it slow and be cautious. The higher the hen is in the pecking order the...