This may sound dumb, but I wasn't there so I have to ask: are you sure they were being killed?

I seldom post on the dog board, so I'm out of the loop - I can't get a grasp of where you were when this was happening.

Pigs can only be killed for food at a licensed slaughtering facility, but I'm sure that's not where you were, or, of course, you wouldn't be so traumatized. I mean, it would probably still be disturbing, but not so unexpected.

Were you at a school that has a vet college? If so, they would surely have euthanized by injection.

Something is wrong, dreadfully wrong, either someone is slaughtering pigs illegally or euthanizing them inhumanely. I can't think of why in the world anyone would need or want to kill a pig except for food or illness.

Maybe questions need to be aked.