A question about the pigs

I am sure you all remember the pig *beep* generators from Beyond Thunderdome.I have to wonder what those pigs were eating. There were a whole lot of very large pigs, and apparently killing them was a crime. What were the rulers of Bartertown feeding them? I know pigs are omnivorous and not terribly picky. But the town was in a desert, there didn't seem to be any crops nearby.If the people were living on stored food and what ever they could forage, I would think they would be very frugal and not leave much in the way of scraps or leftovers and food that had gone rancid would still probably be eaten. So what was there for that horde of swine to eat? Even if they were feeding them things like human corpses and excrement, would there be enough to sustain them?