Several of my hens have bald spots on back right above tail. I first thought rooster damage so i bought saddles. It helped with one but not the other two. I then thought low protein so i mixed layer with flock raiser and supplemented with cat food. It did not help. I did have mites but have treated three times andd total coop cleanout x 2. Did not help. I do see the occasional feather pick and the offender eats them. The spots are totally bald. Plucked clean with no blood. Im not sure what else to try. I dont understand why the saddle helped with one but not the others and my favrolle also is bald on her but which would not be an easy place for a picker. At this point i cant tell who is the offender!