Well, don't be too surprised if he suddenly reappears tomorrow.
My run started life as a 12'x6' chainlink dog kennel. Because of the slope I put it on, the end away from the coop is off the ground, supported by cinder blocks. I bought a roll of 1"x2" welded wire to fill the gap, then a 12" apron, attached with cage clips, on top of the ground to discourage diggers. Lastly, I added 1/2" hardware cloth around the platform that the coop rests on, and 2"x4" welded wire across the top of the run, with a plastic tarp over it for shade & rain/snow protection. It ain't exactly pretty, but on uneven ground it was the best design I could come up with w/o a major cash outlay. I could've used chicken wire in places, especially since it's easier to work with on uneven terrain, but I don't trust it...heard too many horror stories about coons ripping right through it. And, believe me when I tell you, you have coon & possum & skunk around, to say nothing of fox; you're just lucky not to have had run-ins with them yet...you will.