If it is feather picking you might want to put them on a higher protien feed like game bird feed and offer oyster shell free choice. Sometimes feather picking is caused by boredom as well. So far it seems like the flock block I put in my coop is helping but I think I am going to get some hen saddles because the ladies are still bare backed (well some of them) and it could be from my roo. Letting them free range is also good to break up the boredom if that is possible. Some people will hang a head of cabbage to let them peck at to keep them occupied.