I read someone online claiming that 'vegetarianism would be more widespread if people had to slaughter and butcher their food themselves', followed by someone else claiming that 'people did have to slaughter and butcher their food themselves in 'olden times', and vegetarianism was not widespread'.

My understanding from previous comments in this sub (which I don't remember the link for - sorry!) was that food in pre-modern Britain revolved around grain-based staples with some amount of 'opportunism' or foraging, depending on what was in season, with the consumption of meat being pretty low. Hence 'vegetarianism' would be fairly widespread, although as a function of necessity and not really in the same manner that we think about vegetarianism today.

For the sake of being slightly more specific, I am asking whether the 'average' person in Medieval Britain (or earlier, or later if useful) would have slaughtered and butchered animals to eat themselves and how people felt about this (if they had any particular thoughts at all), or if they would get someone else (e.g a butcher) to do this.