If you were a trooper, freshly-shot, would you want a trainee? A work-experience guy? Or would you prefer someone who ALREADY learned and had the right skills.
When I was in hospital a few years back, they kept sending trainee nurses (The trained ones get poached by better-paying private hospitals). I'll tell you, some of those people shouldn't have been allowed to work in a abbatoir.
I know it's rough on the pigs, but you'll note that the vast majority of pigs are killed anyway, and these ones are Anaesthatised first, unlike your average meat works...