Sores On the back of my hens???

[HennyPenny24]

My mother has 6 hens who live in a coop together. There is no rooster he lives in his own coop. They seem to not have interest in him. Anyway, today i noticed one gold hen has feathers missing and i looked and she has a sore bout the size of a quarter on her back thats bloody red, the hens are the ones doing it, there is no way for anything to get into there coop and they do not go around the rooster for he is locked up for being a lil jerk haha anyway, this is on two of our hens. I wanted to know if anyone knew why the other hens are doing this to them????

 

[StephanieD]

I do know once they see RED they will pick at it. I have heard of others suggesting Blue-Kote, found at the feed stores. It will help heal the wound and change the color so they'll stop picking.