Space needed for chickens

Total coop size Don't fool with this just for thermal reasons; although

a smaller coop requires less input to warm, a

larger coop has more thermal inertia and 'swings'

less with outdoor temperature changes, and

also gives chickens more living room.



There is a common misconception that in the cold North you need a small tight snug coop to concentrate chickens' body heat... a coop "small enough that the chickens can keep it warm". On the contrary, there is NO SUCH THING AS TOO LARGE A COOP. By partitioning off part of it (either a coop-within-the-coop type arrangement, or a drop ceiling or hover or suchlike to keep body heat near the roost) you can have the best of both worlds -- a warmer area for the chickens and lots of room for them to utilize when the weather makes them reluctant to spend much time outdoors. Actually I would argue that in cold winter areas, you ideally should have a LARGER coop (more space per chicken) than you would want in, say, Hawaii -- simply because the chickens are likely to be shut in, even if only voluntarily, for long periods of time and you don't need them getting crabby and pecky and starting habits that may be hard to break.

https://www.backyardchickens.com/web/viewblog.php?id=1642-winter-coop-temperatures​