I had a hen that hatched 4 chicks yesterday. Today I went out to check on them and there were only 2. I waited around in the coop for a few minutes to see what might have happened to the 2 that were missing. While watching, several of my 6 month old RIR hens went up to the momma hen while sitting on the chicks. When the momma stood up to defend her space, one of the RIR hens grabbed one of the 2 remaining babies and ran with it shaking it violently. Several of the other RIR hens started pecking it. I ran them off and put it back with the mother hen. Why are they attacking and killing the new babies? I have never had this happen before. I moved the hen, 2 babies and 2 unhatched eggs into a cage where they can't be messed with. When I let them out eventually, will the momma hen be able to defend the chicks?