My EE is 20 months old and molted in September. She grew back all of her feathers as well as her tail but is still not laying again. In the past week, she started losing her tail feathers. Why?? She's happy, eating, clucking, and running around. No rooster in the yard and other 3 sisters do not pluck out her feathers. Why would she be losing her tail feathers again?? Please help with any suggestions.