I built my coop for the wrong number of hens... sigh... they are moving into it tomorrow anyway. I have 8 chicks, which will probably pan out to 6 once they are mature (I have two suspicious roostery "pullets"). My coop is 4' x 4' with a 4'6" to 3'6" sloped roof. Technically I should only have four hens with that size coop but I built it small for more warmth and because I read that hens with a lot of outdoor run space can do with less indoor henhouse space. Hopefully my 6 hens will be happy. They also have a 4' x 4' covered patio that adjoins to the coop, and a 10' x 20' fully fenced and netted run. The covered patio is so that they have access to the outdoors in snowy weather without having to wade around in the snow itself. It also serves as a sunshade in summer- I built it attached to the west wall to prevent the coop from becoming a hotbox in the afternoon sun.
I did not insulate. Instead I built the coop almost airtight with 3/4 plywood and 3/4 siding. I put in roof vents that are to prevent moisture buildup. The vents have flaps that I intend to only close when it is viciously cold, like -10 to -20 and really windy at night, which happens just about every year here for a few weeks. A little bit of silicon caulk made the whole thing very snug. I'm running a 100 watt bulb into the coop for warmth and to keep the light levels higher in the winter which promotes laying. I intentionally built the nest boxes inside the main coop so that the boxes would be warmer in winter- the exterior nest box design that most people use looks really drafty to me. I weather stripped all the doors with recycled bike tubes so that the pophole and nest box access would not have warmth sucking cracks.
Of course, I won't know if all these ideas work for almost a year. Although, in 1996, my town got two feet of snow on June 1st. So maybe I'll find out soon enough if my coop is warm in wintry weather.
-MTchick
