I have a happy little flock of four hens about 10 months old. We just got rid of our rooster two weekends ago because he was being too abusive when mounting the hens. Now, the loss of feathers on their backs are not leaving! It seems as though the feathers haven't grown back! Am I being too paranoid about my girls? Or could this be a ligitiment problem? Could they be pecking eachother? Or maybe they have a nutrition deficiency??? What's going on???