Hello All I'm not exactly new, new but still a novice. I have a flock of ten backyard chickens and they are about 1 1/2 yrs old now. In the fall I thought we might be having a bout with mites during their first molt. Everything seemed to clear up except for Silvia, my Barred Plymouth Rock, she was missing a patch of feathers on her bottom and the skin looked very red.; it apparently had nothing to do with the molt or mites. I put anti-biotic cream and vaseline on it, but it hasn't gotten worse or better. Today I noticed, Agnes, the Buff, pictured in the foreground, has the same patch now. She is missing feathers on her bottom and it looks inflamed. It doesn't seem to be effecting eating, laying or anything else, but sure does look sore. Does anyone know what this is and what I should do? Any suggestions would be appreciated. Thanks.