It’s not the back, they have torn open her neck. I am hoping the skin will attach back without stitches. We had this happen to another hen (and another rooster) before. It only happened to one of the hens then. The hen survived, but she had an area where the feathers never grew back. We were eventually able to put her back with the others. I have been watching this bunch and they seemed to be quick and gentle. This one hen is my old girl who is pretty docile. Going into the winter, I really dont have another safe place to separate the roosters and I prefer they all stay together. If I find that it happens to more hens, I will need to separate. I just wasn’t sure if ther is a way to protect the the rest of them.