I'm in the process of building my first coop, chick's are due April 14th. It's actually built from shipping crates. I've left a 6" space in the front roof line and 2" space in the rear of the roof line. I haven't cut out the door, nest box space, or access door. My question is, do I have enough ventilation, too much, not enough? I live near Charleston, SC so summers are HOT and winters are mild.