I have had what I would call extreme in a hamburg hen. She lost her entire comb from what I can tell. (This was last year). It's never grown back and she's fine. I watched it but didn't do anything as she is so very flighty. It was a little bloody for a day or two and i'm sure it probably hurt but she was a bugger to catch, even in the coop. She stayed outside and we couldn't find her. My BCM roo seems to have dark tips a lot when it's quite cold. In the last few weeks nights get down in the teens and a few in the single digits. Mine must have forgotten what snow is as no one wants to go out, scratch or not. I'm not against treating for anything but like to be sure on what I'm doing. That's why I read here, to get others thoughts and learned experiences. I've never had any problem with moisture in the coop but I think I do now. I've been making adjustments but it's been quite windy too.