I learned this morning that:
Pigs do fight. Pigs' society is hierarchical, so fight over dominance occurs. An incident of pig fight would last maybe several seconds, or at longest a couple of minutes.
More important is what happens after the fight.
They normally make it up. The aggressor and the victim may exchange a soft nose touch, etc.
But often a third party pig ("3pp") intervenes. When a 3pp comes to victim and consoles, victim's trauma drastically lessens. ← This is IMPORTANT