Go out at night with a flash light and look through a window..if you have mice or rats they crawl all over the chickens while they are sleeping. I have seen video on the net and it was very disturbing to watch..I never knew they did that..I know there are mice in the coop, but I have watched the hens reach over and nibble on each others back. The hen that is nibbled on doesn't react, and I have 4 welsummers and 3 astrolorps from that bedroom flock - there is one astrolorp that objects and so isn't nibbled on. She might be the main nibbler, but she taught my 5 year old EE to nibble too. It is a roosting behavior, and I noticed a surge of it when they were locked in the coop for weeks on end with the bitter cold.
they do learn from each other.
funny thing is, they hardly ever eat feathers that have fallen out - down or otherwise.
Delisha that is a scary thought that mice and rats would eat the feathers off a hens back!
And it is totally different than rooster damage. It looks as if someone carefully clipped the tips of the feathers off.
I'll try to get a picture of it. I am just sorry - I can hardly be proud of their condition!