I've got a mixed flock with a rooster who recently came to maturity. That said, since then, one of my hens has wound up missing a lot of feathers on her back. I say it's because she gets chosen more than the other ladies (there are 9 hens total and 1 rooster). My wife fears it's mites. If one hen has mites, wouldn't others have them as well? What I'm wondering is - is this likely from being the rooster's favorite or from something else? Thanks in advance!