Thanks a bunch guys, removing the lights did the trick :)

Ditch the torches & throw in food & wait.

Also don't bother with yellow mushrooms, they won't eat it. Try berries or red mushrooms.

Same applies to any light source. Yellow mushrooms won't let them tame either.

It's the torches; wild boars are "alerted" by fire, and won't eat if they're alerted.

Ditch the torches until the piggies are tamed, or at least move them farther out from the pen.