I have 10 birds in an 8x12. I'm not subject to the sub freezing temps the rest of the country faces. Yeah California. Mid 20s is the coldest it gets and only for a few hours. It heats to to upper 40s during the day. Having the windows open a crack in my case is okay. It is definitely warmer in the coop, the inside water barely freezes.
I also have another non-woods coop with 10 birds. It has wide open windows on two sides, that don't close at all. Birds do fine there too, but it starts to get a little smelly, where the woods coop remains nice inside.
I also have another non-woods coop with 10 birds. It has wide open windows on two sides, that don't close at all. Birds do fine there too, but it starts to get a little smelly, where the woods coop remains nice inside.