long time readers, first time posters. very glad to have stumbled on this excellent resource last year. after one summer and one winter, we're in need of some advise from other cold climate dwellers with regards to frostbite. we got the birds to help with our land's tick problem, after numerous human and dog friends struggled with lyme.. after a few months on the loose our ten voracious black australorps ate nearly every last one! the coop started one wall at a time from all sorts of excess building materials from our job sites. the sides, roof and floor are homemade structural-insulated-panels - filled with 1 1/2" pink foam. we ran ac from the house in pvc underground to power the water heater, as well as two 100w radiant panels to take the edge off. no lights, heat lamps or other elements. we're in zone 5 wisconsin, with extremes of -40 to +100f. the run is on the edge of the forest and gets good deciduous shade in summer. this winter we had the coldest december on record. a few of those days the ladies didn't leave the coop, and we hung a towel over the door. otherwise more or less they seemed pretty happy, albeit with small spots of frostbite on the tips of the combs. after a recent cooper's hawk attack, from which the hen miraculously healed, we finally picked up a rooster. he's an altsteirer, from a local lady who raises rare breeds from greenfire. listed as cold hardy on their website. he's seven months old and thus survived the winter ok. after one week with us, he's already showing worrying frostbite all over his comb. and it's been mild and spring-like - high 30s in the day and low 20s in the night. sunny. not too windy. he still keeps a distance in his new home, so not the best photo. but the tips are all showing signs, as is the main bit in the back... when we got him a week ago.. the ventilation openings are about 2 inches, running front and rear lengthwise. the glass is regular single pane from the hardware shop. when roosting, they can just stick their heads up to the middle of the window (ie a direct cross breeze from north to south shouldn't pass onto them). any thoughts for improving our coop so our winged friends can keep a bit more comfortable? -after previous failures of expensive auto doors, i'm adverse to those. -they wake up much earlier than us, so a door proper would keep them cooped longer -remove window entirely and replace with insulation? -fill in either the front or rear gaps to leave just one side for ventilation? -create a vertical eve above the window so air can escape, but not blow straight in? first island of snow free ground appeared today, and they were quite happy to dig around! thanks!