From doing a little bit of online research, it looks like if you want brown eggs, there are a brazillian different breeds from which to choose cold hardy hens. For white eggs, I'm not so sure. I would not mind having a couple White Leghorns, but are they cold hardy? If their combs get frostbite, I guess it's not the end of the world, but I wouldn't want them to freeze to death or lose limbs or anything like that. I'm basically looking for a lot of egg color variety in my flock, just for kicks, I guess. This winter, my coop got down to 4 F. I figure it could get even colder inside if we saw outdoor temps around -20 F. I'd figure it could reach -5 F in the coop, but probably not much colder than that. Can White Leghorns withstand those kinds of temperatures?