I am wondering if anyone knows of research studies on the possible causes of frostbite. We are doing nothing to prevent it and yet our birds have never shown any signs. During the big cold spell here temps were down to -15 with a windchill of -30 to -40. Our coop has a permanent 3-4 inch gap at the top of 3 walls for ventilation. During the day they can be in a covered run that is enclosed on 3 sides but 100% open along one wall (it's only wire) except during the winter I put up a sheet of clear plastic to block most of the wind and snow. We use a deep litter method of leaves and grass, stirring their bedding once a week and adding more material every 2-3 weeks. I would not classify the coop as low-moisture as the bedding is often fairly wet, though obviously we have great ventilation so that may counteract the high moisture content. We have no heat lamp. There is a 40 watt bulb in a cookie tin under their water to keep it from freezing (the water did freeze overnight when temps were in the negative teens). My barred rock rooster is going into his second winter with a full comb. I look at him daily and he shows absolutely no signs of frostbite on his comb or wattles. Nor do any of my hens with larger combs. Other people that post claim to have much warmer and drier coops and yet their birds get frostbite. Since everything we post here is anecdotal I'm wondering if there are scientific studies on this issue. I have wondered if watering systems could be allowing some birds to get water on their combs which would then freeze. It's the one factor I don't read people writing about much, though once I read a comment where someone noticed that if birds didn't have full time access to fresh water, that when it was brought to them they would be in such a hurry to get a drink they'd splash water on themselves and then it'd freeze on them and they'd be in trouble. Our birds have fresh water all the time due to our heated cookie tin. Thoughts? Info?