Interestingly, if those clean, bald, pink pigs that are farm raised, were released in the wild, it would take just months for them to transform into feral hogs.
A released farm pig undergoes a rapid physical "metamorphosis" driven by epigenetics—where environmental stress triggers dormant "stealth genes" inherited from their wild ancestors.
This includes their bristly coat, their canines which grow back as prominent tusks, and eventually their razorback profile as they shed fat and build muscle. Within a single generation, their offspring would be indistinguishable from multi-generational wild hogs.
Pigs are naturally clean animals. They only roll in mud because they can't sweat and need to cool down.
The filth you associate with pigs? That's what happens when you take away their space and water, so blame it on the humans.