Pigs are NOT dependent on humans and are perfectly capable of fending for themselves. Just ask the feral hogs on my parents' tidal island in coastal Georgia. They are a d**ned nuisance. We keep them out of the yard with an air rifle.
A farm pig is a very different kind of animal from a wild boar, which was the original, and which does very well in the wild. Perhaps the Brits don't have feral pigs.
elegantly penned