We acquired 10 hens last spring that were missing feathers on their lower backs and behinds. We were told they were 8 months old. We treated for external parasites twice with permethrin dust and internal/external parasites with pour-on Ivermectin twice two weeks apart. Their coop & run were also treated with permethrin dust then with linseed oil/kerosene. Everyone has improved and is looking great except for one. She has grown some new feathers, but they are fuzzy or something. I spend a couple of hours each day with them and I haven’t witnessed picking by her or others except one time I saw a hen peck at her behind a couple times. She didn’t pull any feathers. Please see pictures. Any ideas what might be going on? Thanks!