Piggies should jump out of the trees and off the stairs and sky islands in desperation for their lack of food, and either bounce or go splat leaving a pile of meat.
If they land on a Glitch, it kills the Glitch, sending them straight to Hades, and the Piggie lives.
Hungry piggies in the mines could demand food, swarming the miners and blocking the pick - "oops, your pick hit a hungry Piggie". Or they could just eat the miners :)