We just purchased and built ours and I'm worried it's too small! We have four chickens. Our size is 4.5 feet high, 3 feet wide and 5 feet long. They will have very little free-range time as our yard is small and mainly garden boxes and a deck and we don't want them in/on either of those. So most their time will be in the run and I want to know if that size is too compact. Thanks!