I have 7 girls, no rooster. All together since I purchased as baby chicks. They are not 16 months old. Feather picking started after first molt and I wasnt able to control it with vinegar in the water, vicks on the feathers and bald spots, more protein, hanging cabbage in coop, etc.... My girls have a 14 x 14 coop with lots of post for roost and two laying boxes. They have access to a large yard where they free range from 7 am to 7 pm. Yesterday, out of desperation I applied the peepers to all 7. My friend who raises organic heritage birds told me that I should start them on antibiotics until I remove the peepers. Not sure that is necessary. Any suggestions?