I believe butchers like to say: "We use everything but the Oink." Apparently,
that is true but some of the uses surprised me. Pig hair in your bread? Really?
Friend of mine works at the packing plant nearby, he's one of the analysts that does the food analysis and makes the product RDA labels. He says "We use everything but the squeal".
If it's not table food, it's pet food, or fertilizer, or animal feed supplements, or raw chemical stock for industry.
For instance, the gristle is melted down to form collagen, and that is sent off to make Jello.
Bet you didn't know your Jello was pig-based?
Oh, and I remember asking him what about all that blood, surely you just run that down the drain? Nope. "Lipstick". (yes, really)