We're finally constructing our coop, and I just want to check on the dimensions of the henhouse. I think we need 12 inches from the ceiling to the perch, right? So here's my question. We're building it off the ground, and I was planning on allowing space underneath for the girls to cool off during the hot days . . . there'll be a space about 4'x7' under the house. I'm making the space under the house about 16-18'' high - is this enough room for them to be comfortable underneath? I don't want anyone getting stuck. This means inside I'll have 12 inches over the top roost, and about 20 inches under it. Does this sound ok? We're still at the point where I can adjust these numbers if anything needs to change . . . but I want to get it finished this weekend if possible. I think our girls are ready to move out of their box.