Fed to Pigs

I hear the best thing to do is feed them to pigs. You got to starve the pigs for a few days, then the sight of a chopped-up body will look like curry to a pisshead. You gotta shave the heads of your victims, and pull the teeth out for the sake of the piggies' digestion. You could do this afterwards, of course, but you don't want to go sievin' through pig shit, now do you? They will go through bone like butter. You need at least sixteen pigs to finish the job in one sitting, so be wary of any man who keeps a pig farm. They will go through a body that weighs 200 pounds in about eight minutes. That means that a single pig can consume two pounds of uncooked flesh every minute. Hence the expression, "as greedy as a pig".

—Brick Top, Snatch

A somewhat common staple in criminal and horror fiction. In a terrifying twist on the Gluttonous Pig trope, serial killers or mobsters use a secret pig farm to dispose of their victims' bodies.

It's most likely Truth in Television. Pigs are omnivores rather than vegetarians, meaning that they do indeed eat meat if they are able to come by it. No matter how special and worthy of respect we consider the corpses of us humans, it's the same as any other carcass to a pig, meaning that they will chow down on it.

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?

Not only is this trope plausible, it's also downright horrific due to the fact that it not only involves an invocation of humanity's Primal Fear of being eaten, there's also the chilling factor of role reversal added to this. Outside the pigpen, you eat pig (if you aren't a vegetarian, that is). Inside our killer's pigpen, however, pig eats YOU!

Subtrope of Disposing of a Body and Eat the Evidence. It's also a Darker and Edgier subtrope of Gluttonous Pig.

As a Death Trope, Spoilers ahead may be unmarked. Beware.

Examples of Fed to Pigs include:

Comic Books

In Mark Millar's Wolverine run, the Gorgon and the Hand lured Wolverine into their territory by kidnapping the son of one of his old acquaintances. After things come to blows and the Gorgon gains the upper hand, he reveals that the boy is long dead, fed to the Hand's pigs.

Film

Hannibal took this trope Up to Eleven.
Daddy's Deadly Darlin features a serial killer who feeds his victims to pigs.
Brick Top from Snatch keeps a group of perpetually starved pigs on hand to eat, and thus dispose of, the bodies of people he kills.

Literature

A non-criminal example from The Last Apprentice. This happens accidentally to Mother Malkin at the end of the first book. She shouldn't have attempted to flee through the pigpen while she was shrunk and the pigs were agitated.
One of the participants in the Deadly Game in Friday the 13th: The Jason Strain is a serial killer who apparently disposed of her victims by feeding them to her hogs.
In John Ross' Unintended Consequences, Henry Bowman successfully defends himself from an ATF raid attempting to plant drugs, counterfeit money and terrorism plans in his gun dealership. At the time, he thought they were a biker gang - but afterwards he decides if The Government wants to declare war on him, he'd just have to retaliate. Starting by disposing of the bodies in a pig farm(minus their indigestible hair and teeth).
"Pig Blood Blues" by Clive Barker has a new guard at a juvenile facility learn that a missing prisoner has managed to transfer his soul into a giant pig in order to avoid death. Because he knows too much, he ends up getting thrown in with the pigs... while alive.

This is the state of the beast. To eat and be eaten.

Harry Turtledove's Prince of the North has a moment when the hero and his army come across a village where monsters slaughtered all the people. Seeing some chickens and pigs rummaging around, the troops suddenly decide they really don't feel like eating pork or fowl tonight.

Live-Action TV

Mr. Wu's pigs in Deadwood are used to eat dead bodies.
An episode of CSI showed how a killer used pigs to get rid of the remains of a woman he killed.
Used in the Criminal Minds the two part season four finale, "To Hell..."/"...And Back" by a mentally-challenged pig farmer, who was manipulated into killing people by his quadriplegic brother.

Video Games

Manhunt: Piggsy, a sadistic psycho-killer in a mask made from a pig's head, believes that he's a pig, and feeds off corpses that the Cerberus provide for him.
On one path in Critical Point, you can see a flashback of the hero suffering Cold-Blooded Torture in which he had his right arm hacked off piece by piece, starting with the fingers. Each piece was tossed to a nearby pig after being cut off.

Web Comics

Mordecai Heller uses a pig farm to dispose of a body in Lackadaisy. His accomplices, Nico and Serafine, were a bit disturbed to see he took their "joke" about doing so at face value...

Real Life

The Kray Twins allegedly had a man named Frank Mitchell killed and fed to pigs.
Also was allegedly very popular in Sardinia/Sardegna, where kidnappers would often dispose of a deceased victim by feeding it to the pigs.
Canadian serial killer Robert Pickton allegedly murdered prostitutes and fed the bodies to his pigs. (This was in addition to evidence that he disposed of bodies in rendering vats.)
This is said to have been the way IRA terrorists in South Armagh disposed of the body of foolhardy SAS captain Robert Nairac at the height of The Troubles: Nairac attempted to pass for Irish in a terrorist pub, was detected, tortured, shot and his body allegedly fed to pigs.
Allegedly how some Frenchmen disposed of a pair of Les Collaborateurs who had betrayed several families to the Nazis. According to the story, they didn't bother killing the collaborators first — just left them tied up in a quarry with the hogs ... and then came back a week or so later and had a big barbecued-pig feast. Cannibalism by proxy....