I'm in Colorado (near Denver) and we are in a very serious cold spell. This is our first year with chickens and I want to make sure I'm doing the right things for them. The last two mornings were -9 and -8 when I went out to let the chickens out. They both had a little frost on their backs!! There was also just a tiny bit of frost on the battery powered lights we have inside the coop this morning. I'm guessing our coop isn't ventilated well enough and I need to fix that. So I need some advice from others who have a lot more experience. I'm posting pictures and dimensions so everyone knows what I'm dealing with. We don't have electricity out there and the coop is so small I wouldn't want to put a heat lamp out there for fear of fire. I run fresh water out every couple of hours to them. They have a 6 by 6 run that is covered, and has clear shower curtains on the South and East sides to block the wind. The shed provides wind protection from the North. The West (window side) has a fence about 6 feet away that helps to cut down on the wind. I have about 6 inches of straw down in the run right now. They spent the morning today on their outside perch and scratching around in the straw. Our chickens only go in the coop at night. We leave the gate open to them so they can go in, they just don't normally unless they're laying an egg. This is our coop. It's 27 1/2 " by 20" with two perches plus the nesting box on the end. The one perch is right in front of the window near the door so the birds are not using that one so far this winter. I think there's too much of a draft there. I have about 5 inches of straw lining the bottom of the coop. It's almost covering the perches. The window is 6 1/2 by 4. I thought the window might be making them too cold the other night, so I pinned a cloth in front of it like a curtain. After the first morning of frost on them, I took it down but leaned a large piece of wood on the coop to block the wind but still allow air flow. Had frost again after the changes. The ventilation triangle on top is about 2 by 6 1/2 at widest points. This is the backside. No ventilation holes. There is about an 1/4 gap under the back eve which I am assuming is for ventilation The colored area is their door. I hung a slashed "curtain" in front of it when the weather got cold. Normally I leave the coop door open all night, but the last three nights have closed it. The curtain will come down when the weather warms back up. I drilled five 1/2" holes in the top corner this afternoon hoping it would help a bit. I'm going to have my husband cut out a triangle where the holes are that matches the other side this weekend hopefully. I know they need plenty of ventilation but not drafts. My thought is to add the matching triangle ventilation on the other side of the coop where I drilled the holes and possibly cover the window with a loose piece of burlap that would allow air to move through but block some of the wind. Right now we only have two chickens but would like to add one or two more after this cold spell moves on. So would we need to add even more ventilation if we had more chickens or should I leave the coop door open since I have the curtain up to block the wind? I'm also trying to prevent frostbite on their combs and waddles. Yesterday I applied Vaseline in the morning and about an hour before they went into the coop. This morning they had little block spots on their waddles and combs. The black spots are throughout the waddles, not just on the edges. I applied more Vaseline this morning. I found some bag balm after lunch and went back out there to apply that. While rubbing it around, I noticed some of the black stuff rubbed off so I'm wondering if it's just dirt sticking to them since they're scratching around. Here is a picture of the one after having bag balm applied. Here is the other, also after having bag balm applied. They look so funny after scratching around and having the straw stick to them!! Thanks for everyone's help and advice. I'm such a worry wart and want to make sure I'm taking good care of my chickens. .