Corners are a problem for a lot of birds. With our pheasants that's the location they almost always decide to go vertical. We keep that down a bit covering the bottom 24" of their cage in burlap so they can't see out as well. This makes them want to fly out in pretty much any random location...
I guess chickens that aren't loud enough to annoy the neighbors would be the idea.
I already have a coup that's 12' x 8' and 7 feet high. It's not going to be fixed to the ground, maybe on wheels or something.
If I had to have a fenced covered run I may as well keep the pheasants. And that...
Soon, or at least, hopefully soon the family and I will be moving. For now we don't have chickens at our house, it's not an ideal location. But I do have Pheasants. 4 Lady Amhersts, 3 female and 1 male as a good beginning step to prepare the family for chickens. I have had many birds in the past...