One word. Yotes. Most deer head for water when hurt or ill, but that doesn't seem to be the case here. Coyotes are more capable than most give credit for, but I have seen it happen where I hunt. I have found piles of deer bones like that, among other critters. That is likely where they drag to feed.

I suppose it's possible someone may be piling poached deer there, but heads would be gone. Start hunting the yotes.