For the best truffle setup, start with a deluxe barn from marnie's and fill it with about 10-12 pigs at 16,000g each. The basic idea is pretty straightforward, just get them outside every day except during winter or rain and make sure to fence off a nice sized area to keep the truffles concentrated.

Getting your pigs to max friendship is crucial, since they'll dig up around 3 truffles per day when they're happy. The foraging path really makes a difference here, with gatherer and botanist professions turning this into a gold mine. Something worth noting - truffle oil sells for more with the artisan profession, but without it those iridium quality truffles are actually better to sell raw.

Clear out any debris in their pen and maybe lay down some paths to keep things organized, though the truffles can technically spawn anywhere they walk. Each pig needs about 100 tiles to roam effectively, and it's good to check for truffles both morning and afternoon since they'll keep digging throughout the day. Make sure to grab everything before the season changes or they'll disappear.

Once you've got the full setup running, you're looking at around 30-40 iridium truffles daily from a full barn, which turns into some serious profit especially if you're processing them into oil. Just remember to switch gears in winter since the pigs stay inside then.