Tim, using dogs, donkeys, fencing tricks, weed control, etc to protect your livestock is like putting armed guards around the next World Trade Centers to stop terrorism. You must attack the predator problem at its SOURCE. Doesn't matter whether its feral hogs, wild dogs or coyotes you need to get an experienced trapper to evaluate the kills and identify the problem animal...then hit them where they live, before they get to your pens. Traps work while you sleep and are proven to be the most effective ongoing conrol known to property management. Forget the search for the one-shot remedies and find a great local trapper who will stay with you. More help if you want when I get home tomorrow.
Dan VS