No kill plants in the US although some of the tribes keep threatening to put one in. Used to be when ones nag got rode down one could still earn a few hundred off it as chicken/dog feed. Now is costs one to get rid of a steed. Vet to kill it and equipment to bury it. Here in the west, so still go out into remote areas a put a slug in its head.
Pre-protection days trappers would drop a feral horse, let it sit for about 2 days, then ring the area with traps. Great coyote bait. Cowboys short on cash would round up a few and sell them for pet/chicken feed. If one scheduled a roundup, he could put out the word, and every wrangler in the region would show up.
