I started out by covering my run/coop with bird netting, 6' tall fencing, coyote proofing (chicken wire laid flat on the ground under the fence to prevent digging), solar night lights, the red-blinking-eye box, coyote urine sprinkled around the perimeter, and traps. And I lost chicken, after chicken, after chicken to possums, raccoons, snakes, bobcats, and dogs.
This year I moved the chicken run, and when I did I added a hotwire all around the bottom, about 6 inches above the ground, and over the gates. Haven't lost a chicken yet, except two young one that got stuck on the hotwire. I use Roundup to keep at least a foot of bare ground on the outside of the fence; keeps tall grass from grounding it out.
Oh, and we fixed the chicken electrocution problem by adding a photoelectric cell. It turns the shocker off as soon as the sun comes up, and turns it back on at night, when predators are a problem.
It cost about $100 to hotwire 225 linear feet of the fence. Best money I ever spent.
Kathy, Bellville TX
www.CountryChickens.com