On Stardew Valley's official wiki's Pig page there is a passage:
Warning: Pigs will NOT PRODUCE ANYTHING if they are at a high enough mood and friendship to produce a "Deluxe Product", because the animal type cannot produce Large or Deluxe products.
My question is based off that – does maximizing your pig's friendship reduce their ability/chance to find truffles? If yes what is the most optimal friendship level?
Best Answer
This is actually a glitch in the game to be fixed soon. The optimal friendship level can be achieved by not petting your pigs and just letting them outside and making sure they have enough grass. It's actually easier than what is intended for it to be.
It has been now fixed in 1.2.