I was thinking about having a small pig conveyor start running in the background in a loop when the player enters one of the first areas. I gotta find a way to get Minecarts to pick up mobs though since they don't seem to stay in place if they're already in a Minecart when the map is loaded.
EDIT: And indeed, I've found a way of doing just that. Although it's a little temperamental.
In fact it's so much less temperamental
than the original crappy system I was using for this that I wish I had thought of doing it this way before filming. Would've saved all that pissing about earlier. :S