I'll start by saying I've just spent a few hours reading frostbite posts, and am just not sure they answered my questions. Generally they say to keep them dry and well ventilated, I think I'm doing these things, but maybe with specific photos someone can help me further and point out specifics of where I'm going wrong. I live in southcentral Alaska, and this is my first winter with chickens. I just came home from 9 days away for work, and found my roo and two of my hens have black tips on their combs. Pretty sure it's frostbite. It just looks black on the rooster, but one of my buff plymouth rocks has some white puffiness under one of her black tips. My husband didn't seem to notice, so I don't have any information about how it developed really. So here's some info, it's dark so no pics of the chickens black tips but looks just like the dozens of other posts I've seen that are frostbite. I have 12 hens and 1 rooster. Mostly plymouth rocks, with 3 light brahmas and 3 silkies. The coop is 8x8 walk in, with the front about 9' high and the back about 5' high. It's a foot or so off the ground. Floor, walls, and ceiling are all insulated. I have lots of windows in it for summer ventilation, but they've been closed up for several months. The ventilation I have left are two vents on the north and south sides of the coop at the very top front, and then an 8 foot long strip along the high front side. Photos below are during coop construction. So, I thought I had plenty ventilation, and the summer went great. Now I'm starting to wonder. I have yet to see ANY frost or condensation inside the coop. Their poop is always frozen though, not sure if this is good (less fumes/moisture?) or bad (freezes fast so shows it's cold in there?). The pic below shows where their roost is, and also that I'm using sand for the bedding. I've spent literally days reading posts about how cold sand is, and I will probably be putting down hay over the sand soon, but thus far their feet are all doing just fine, and since the sand seems to retain a lot of the moisture I don't think that is a problem with the frostbitten combs. Temperatures. It's gotten down to about 0F, with windchill it's been down to -12F. The shot above with the sand is taken from the pop door, which has remained open in all except the coldest nights before I left (I'm assuming my husband never closed the door). When it's open, it does have this arctic entry for them pictured below, and the roof of that is insulated to retain heat. Other possible problems... using a bucket nipple waterer? Are they getting water on their combs and it's freezing? Is my ventilation just woefully inadequate already? I know you can really never have too much, but unless I lower the roost I don't see where I could put more even if I did feel like cutting holes into my finished insulated coop. Should I not be letting them free range in the snow? Their run is 10x20 and covered, but I like to let them out when I get home from work for a few hours, and they're out all day on the weekends. The other weird thing is WHO has the frostbite. The partridge plymouth rock roo has it on his obviously huge comb, but so do the two buff rocks, and they have just average sized combs. My barred rocks have the largest combs and no sign of frostbite. I will be paying attention to where they're sleeping now that I'm home and aware of the problem, but any tips/suggestions would be much appreciated. We haven't gotten any eggs in a few days, we had been getting about 7 a day before I left. Light is definitely diminishing, right now we just have a light bulb in the coop that's on for 2 hours in the a.m. and 2 in the evening. Thanks in advance for reading and posting!!