Forest fed pork depends on the area. New England/ Eastern Canada might have more as the pigs roam and eat acorns and mushrooms and roots. West coast forests are more acidic and the pigs wouldn't find as much that they can live off properly. Pasteurized pigs usually get the traditional "slops" of veggies, milk, sometimes potatoes and corn still on the cob. I am thinking because they eat the cob and all it would be better than dried corn feed.
I knew a guy in Alberta who had a bumper crop of potatoes one year and couldn't get rid of them all, so he just kept feeding them to the pigs but never gave them anything else. The pork ended up tasting like old potato. Not so great. The more diverse the diet the better the flavour!