How much run space will you provide for your chickens, or will they free range? As you are in a climate where winter can be harsh, your chickens will spend more time in the coop than they would if you were in a warmer, more mild climate - as such, the space available is even more important. *I* would use the generally accepted rule of thumb of a minimum of 4 square feet per bird inside and 10 square feet per bird outside --- so, at 16 square feet inside your coop is actually more suitable for 4 birds, not 8-10 or 12. You also have to keep in mind that if you provide feed/water inside the coop you need to deduct the amount of floor space taken up by those from the available space for birds. A seemingly "big" coop can start looking awfully small rather quickly when you stop to think about all you might put into it. Can they survive in less space than the above minimums - of course, but for me the idea is about providing more than what is necessary for survival. Overcrowded conditions can lead to a number of issues - from health concerns, difficulty in maintaining good cleanliness, aggression between birds, etc
