What would be a good size of a run for say about 20+ chickens? I have a coop that is going to be 10x12 with two openings on each side for two runs. It seems like my chickens like outside better than a warm coop, so I want to make the run nice and special. Is 10x12 big enough for this amount of chickens? We only have about 12 right now, but I have chicken fever, and you know what that means! ETA: How many windows need to be on a 10x12 sized coop?