My flock used to have that problem. We think the problem was either lice because we noticed they all had lice. Or the fact we left their light on 24/7 over the winter. Chickens in the light all the time end up going mad, like we would if we had the lights on all the time.
Your chickens more than likely have red mites. You will have to clean your coop thoroughly. Take out all bedding, put down Seven Dust all over the floor. Before this, spray the crap out of the walls with pymethrin. You will have to do this twice. The second treatment should be about two weeks after the first one. Also, dust your chickens with Seven Dust under the wings and thier butts. I had this problem several times, usually after its rained ALOT in the spring. I also had a problem with lice when I< dummy me> accepted some hens from my neighbor and didnt quarantine them first. Took me a month to get rid of those suckers. I know this is an old post, and hopefully you have come up with a solution in the meantime. If not, hope this helps!