I know you need 4sq feet per bird, but how tall does the coop have to be? I have sen some the size of sheds, and some that look only about 2 ft high. Is there a standard? We have a mix of standard and bantam birds and we are debating between a new shed or building a coop. Also we live in the Mojave Desert. It is really hot during the summer but we get really strong winds and can get below freezing in the winter. Would a coop that is open, a warm weather coop, even be an option here? Any suggestions would be greatly appreciated. Help!