Hi. First post, I'll try not to sound to ignorant! My wife and I want to get a couple of chickens and we're looking at designs for coups and runs. There are very beautiful designs here and I think it's great they are free. As a kid on Grandpas farm the chickens were never boxed in. They had there coup and a fenced in area, but there wasn't a roof over top of the run. All the designs here have roofs over the runs, is it necessary? I know they can't fly, but do they jump hi? If I do a 3 ft. fenced run will they, pardon the pun, "fly the coup"? Thanks for any help!