What would be a good solution to keep predators from climbing on top of this enclosure?

[chickensahoy96]

Here is my 12x12 chicken run. It has 1 inch welded wire on the sides and base (as a predator apron under the gravel). And then a 1 inch poly net on the top. This net concerns me because it a large animal can easily chew through it if it can climb over. I tried an energized polywire strand with hook insulators but it was too fussy and was somehow energizing the welded wire. I dont like the idea of accidentally shocking myself or otherwise causing harm (like barbed wire would). I was thinking of 3 strands of piano wire 6 inches tall which wouldn't hurt a chicken if they were let out and tried jumping on it, but I imagine would be incredibly painful to grab and climb over.

In the background is also a 55 gallon water drum with watering cups (I fill it up with softened water), and a 5 gallon feeder with the chicken feeder ports installed. Works great and the best part about this setup is I only have to check on them once a day when I get the eggs. The water lasts for atleast a month and the food about two weeks (I even put a water gauge to easily check the water without opening the lid and inviting algae). I actually keep the door always open too since I don't think it would matter in this case. If a raccoon breaks in it would most likely hang out here until I come by with the double barrel.

 

[Altairsky]

I personally would try to upgrade it to a walk in run with a proper solid roof. I don't know your climate, but even without large predators climbing it, if I had this setup in my climate, hail in summer and snow in winter would collapse the top netting. Not to mention rain turning the run into a mud pool for 6 months a year.