I got a flock of 15 layers, this one has been mostly bald since i got them, the people i got them from wanted to put her down, but i want to give her a chance. She eats well, they are free range with layer pellets free choice. She is energetic and happy, when not being picked at i think she is the low hen. Her feathers are finally coming in but i see some dark crud by her oil gland. I hope its not mites. Any ideas?