I hope someone more knowledgable than myself replies.
However I give Murphie cattle femurs etc but have the butcher cut them into pieces so she can work out the marrow. She ends up chewing on the ends and giving her gums a good workout anyway, before she leaves them lying around on the lawn. I don't really consider those food per se, but more of a treat/toothbrush kind of thing. Not sure about pig bones, but I've seen some pretty big pigs, with bones that must bear a LOT of weight heh.
Good luck,
Mona