fizzle chicken not growing back feathers!

[ironsfamilyfarm]

I bought a young Cochin Frizzle at my local feed store in the spring. He had been picked on by the other chickens that were in the cage with him and he had no feathers except on his head neck and wings.... his back and butt are bald as they can be! He looked pitiful and it tugged at my heartstrings so I brought him home thinking that with a little tender loving care he would soon grow back his feathers and be beautiful! well, summer is over and my poor little Frizzle is still bald! a couple of weeks ago I noticed that a few of the feathers that had grown in have now come out. The rest of my chickens are in mold right now could he also be molting? Do Frizzles have any skin issues? The skin I can see appears normal but I don't see any traces of feathers coming in. I am worried about him freezing to death this winter. Why are his feathers not coming back? I have not seen any of my chickens picking on him and he seems to get along well with the other frizzles that I already had. Advice or suggestions would really be appreciated. Thank you.