This is my other coop - similarly built. You can see the door on the left side of the picture. It was taken from our old barn. The first run I showed you has a door made with 2x4s and wire. I don't have a picture of that, sorry. It's just framed with the lumber, 2x4" welded wire attached to that, and then DH put braces in the corners to keep it somewhat stable. Both of my coops also have people-doors. When I first started chicken keeping, I didn't think about that - just had a 4' high run, with no easy access from the outside, and just the pop door from the coop. It was fine until one died out in the run and I had to go get it out.
