I "chicken sat" for a friend of our who went away over the long weekend and I noticed that a number of her hens were missing several feathers. One had a huge bald spot on her back, other had them missing around they're legs. I just found it odd and wondered if it was because she had so many in a small coop during the night? I mean there is enough room for all of them to roost to just fine and they are out all day with acres to roam. I have about half as many hens as she does and I don't have this problem. Is it because the hens are trying to assert dominance?