Duster, I am unsure what that is. Is it just skin missing feathers or is it a lump? Any other symptoms?
It's missing down where feathers haven't yet grown in... not a lump. Sorry the photo isn't that great, he is the most enormous fighter. His green iridescence is already showing on the "big boy" feathers he has. Is it possible that he's just a super slow feather-er? I have only seen a couple feathers around the coop and they aren't his.
Skin doesn't look red, just pink.