It sounds like the dog, though it is kinda strange that he ate on him. He must have been at least hungry. I agree with getting a donkey or even a llama. I seen one of my llamas nearly kill a pit lab mix one time. I if she had about 100 more feet of pasture she would have. They don't bother my dogs though. This dog was getting a little close to her herd. But the point is, if it was coyotes, then that will help a lot, and if it was the dog, and ac can't keep him and turns him back over, which is what they seem to do a lot, then again, that would help. I think a small donkey would be the better choice in your case. Or, a Great Pyrenees. I know that at this point the thought of getting another pet so soon after losing a beloved family member is rather appalling, but for the safety of your other animals I would definitely recommend getting a guardian animal. Even if you have a rifle leaned against your door, you don't always know when something is happening.
Again, I'm so sorry for your loss. He seemed like a sweet pony and I'm sure your little boy is heartbroken. :(
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