We had similar situation - old coop was in bad shape, drafty and we lost chickens due to build up of moisture in the winter so were looking for a new coop
Found the 1920s Woods Fresh Air Poultry book online and decided that was our ticket. (book online at Woods Fresh Air Poultry House
-- discussions here: Fresh Air Coop Discussion
Used pallets to build the frame on store-bought skids and purchased lumber for roof - used cast off (free) windows for the clerestory. 8 x 12 (Woods design is based on golden ratio 1.6 - so basically a square main area - in our case 8x8, with fresh air "porch", in our case 4' - so not exactly golden but darn close). Baffle board will be installed on rear rafters today to further seal against drafts as the temps will decrease the next few weeks and snow continues to accumulate toward our average of 200"+ :)
Our 9 chickens and 1 rooster LOVE it, and even though it has been below zero several nights, no signs of frostbite. Chickens are roosting normally (not clumped together) signalling they are warm enough without needing extra body heat from other chickens.
Solar power project begun but not finished for the season extension bulb and the water warmer so using extension cord power at the moment. Needing a larger panel and larger battery for the warmer. Did have a small aquarium pump in the 5 gallon water bucket and that kept water in the bucket from freezing but the nipples were freezing up so had to go to a small (250watt) submersible heater.