Yes, Maybe someone can help us out here. From reading all over the internet, its not a molt because that starts at the head. And I cant detect any mites or lice on them or their coop. But just to be safe we are putting Dietomatious Earth in all their bedding and on their feathers, and read somewhere that a good way to get it on they is to put some DE in a sock and kind of gently wack( LOL) the chickens and the affected areas with it. It is quite possible that we have one chicken that is plucking out the other chickens feathers( all are affected accept one, which is suspicious). And it could be due to bordom, or a lack of protein in their diet. So if they have a lack of protein sometimes a chicken wil pluck out and eat the other chickens feather because feathers are made up only of protein. So if it is bordom we are going to try a sugesstion that was read somewhere and hang some produce(such as cabbage) from a string in the coop. Give them something to do. Ours we let free range during most of the day. But maybe when they are in the coop they dont know what to do with themselves. If they are lacking protein then find a way to give them more protein, our are organic chickens, so we need an organic protein. I have hear that you can give them hard boiled eggs. But the only thing that worries me about that is I don't know if they will get a taste for eggs and start eating their eggs before I can get to them. So I will also be looking into some other organic options for protein. Also more protein in their diet will help the chickens who have suffered feather loss regrow their feathers.