We have 2 one-year old brown leghorns. Currently, our coop is about 33 inches by 40 inches, and i think 40 inches tall. (made from pallets, with fiberglass roofing around as natural light filtering "siding"). The birds free range during the day, and we are working on a run design for when we go on vacation. We are considering adding 2 or 3 birds to make it a "flock". Are there certain breeds that get along better? We need cold tolerant birds here in north Idaho, where the winters are long, and we can have sustained subfreezing temps, day and night. Is there a minimum "magic number" for a happy flock? We don't want to have to build a larger coop and don't want too many eggs, LOL Any suggestions are welcome. I'm totally new to chicken keeping, got the birds from our neighbor 3 months ago.