How high would folks suggest building a topless pen to house Cornish X in my garage? Could I get away with 3 feet or would they be escaping? Not life or death (obviously no predators in there) but would like to keep them kinda contained. We're talking about 8-10 birds and I should be able to make them a 9x12 inside pen. Thinking I'd use a side garage human door to allow access to a chicken wire roofed pen outside during the day. I'm sure they'll be stinky--the joys of suburbia--may never do this again but thought it's worth a try!