Help! My hen's comb is turning purple and black! She is about 2 and a half years old and and has been de wormed. She is one of 3 chickens in my small backyard flock. They are all ex battery hens and I have had them for about 6 months. I noticed that her comb started going purple at the tips about a month ago, and it has been getting worse. She has started losing weight but she still is eating a drinking. Is it avian pox? Do you know what's wrong with her? Can it be treated?