We live in northern Illinois and we're getting into some extremely cold weather. This is our first winter with chickens. We were given a small store-bought coop that our chickens were in all summer while we built a coop out of an old work truck cap. We completed it and moved the girls in about a month ago and everything has been great until now. Last night, it was about -6 in the coop with 86% humidity. (We bought a wireless thermometer that also monitors humidity.) We had every ventilation option open and could not get the humidity down. Our poor girls got frostbite, even with Vaseline on their combs. Today I moved them back into the old coop in hopes that it is better ventilated. So far, it is a little better. It currently is 6 degrees in that coop with 73% humidity. We are hoping the frostbite won't get worse. Anyway, we are trying to figure out how best to modify the truck cap coop to improve ventilation. I'll attach pictures so you can see the setup. There is a residential roof vent up top and we were leaving the ramp open but that is not enough. Would adding more roof vents help much? The cap has tool boxes on the sides. We turned one of those into the nesting boxes and left the other side as is to use for storage. I though maybe we could cut a big hole in the toolbox on the other side and add the wire fence stuff (like what's around the run), creating a big "window". The door to the toolbox would act as sort of an awning over that window. Another idea was to completely modify the roof and rebuilt a roof out of wood in an A shape and add plenty of smaller vents. Any input, criticism, ideas are appreciated. We are new at this and want to give our chickens the best, safest coop.