I think it's much more likely that the deer simply died right there and was scavenged. There's also the possibility that the deer was weak and dieing and the pig took the opportunity to finish her off. I find it highly unlikely that the pig actually killed a healthy deer. And if it did somehow spook a pig in a wallow and the pig swiped at it, a bad cut still would have allowed the deer to run a long distance before dieing. Therefore, probably a coincidence that it was dead next to a wallow.