WARNING...Sensitive material
I recently did some research about this for a book I was working on. I was trying to find if you could identify remains through pig excretion. Here is what I found:
A pig's body is also quite up to the task of digesting almost every part of the human body. They can not only chew and digest human flesh, they can also readily digest human bone without excreting a noticeable trace of it. Of course, they can't quite chew the skulls and longer bones that humans have, but if our killer has enough determination, they can just break said bones into smaller, more chewable pieces. They also can't digest human hair and teeth, but it should be a simple matter to shave your victims' heads and pull out their teeth before chow time, right?
Source:
Fed to Pigs - TV Tropes