Hen getting under another with baby chicks

[MTrimi]

I have two hens that were sitting on eggs together. Now all the chick's are hatched. The bigger hen has become Mama, and all the chick's nestle under her. The other hen is also trying to get under her with the baby chicks. I'm afraid she is going to harm the babies, so we removed her from the chicken house, but she won't go with the other chickens, and just sits outside the chicken house door. Why does she try to get under the Mama hen? Is she trying to be the Mama, or does she think she is one of the babies? Is it safe to let her go back in there or should we keep her separated?

 

[Mvan42]

Can you give her a couple of the chicks? If she sat broody for all that time she may want her babies.