The run ur talking about is that the one in ur profile pic caus either looks fabulousFor our extended run. We used 2" × 4" 5' welded wire. No roof. The hens don't bother to fly out. I know there is risk that predators can dig under or fly over. But so far so good. So for us the risk seems about right.
The run is hw cloth, including apron and full roof. When they are in there they are in a pretty secure location.