I was having a mysterious comb problem with some of my chickens, mostly my BO roo. When it got really cold out, like in the low twenties or lower, my chickens would occasionally have bleeding on the very tips of their combs. My rooster has a massive comb and had some frostbite, so I figured that that was the problem. But then one or two of my other chickens had the same problem, and no evidence of frostbite. This was happening mostly in the early winter, when my metal waterer would freeze up and I'd have to take it inside once or twice a day and thaw it out. Then I got a base heater for it, thank goodness, so much easier. The comb problems seemed to stop at that point. But it occured to me, watching a hen eat from my feeder, which is also galvanized, that something wet could stick to that feeder when it's super cold out. You know, like your tongue freezes to a metal pole in winter! Could the chickens have been getting their wet combs stuck to their frozen feeders, and then making them bleed when they pulled away?? What do you think??