Last week we found one hen dead in the hen house. Tonight after I put the hens back in the hen house after grazing I closed the door.....a few minutes later we heard fighting. I opened the door up to find 4 bully hens attacking one lone hen. She was coward in the corner. They chased her to another corner and yet another one till I stopped the fight. They've always gotten along together. Hubby did find a suspcious pile of dirt by the hen house about a foot away. Looked to me like an ant mound but there were no ants. We live in PA it's not like we have TX fire ants. The one hen has lost a lot of her feathers on her back. I'm not sure if they are picking them out of her or what. Why would my hens fight like this? They are all the same age. No rooster for almost a year.