Regardless of the boar taint debate, which could make up a whole new topic, what this comes down to is whether castration without anaesthetic is ethical or not.
Surely, the bottom line has to be, does castration without anaesthetic cause unnecessary suffering? (male readers cross your legs now - oh, sorry, you already have!).
I'm not opposed to the procedure being carried out properly, in hygienic conditions and, of course, under anaesthetic, but someone doing half a dozen at a time in the barn, with a possibly grubby penknife (as I've seen it done) is another matter. How can anyone endorse the practice of causing an animal such severe pain at just few days old? Carry on castrating in your own way, if you feel it's right, but I think it's barbaric and nothing will change my mind.