Preparing pork belly: Odd barn yard flavor
Having raised hogs I can say that the actual feed can make a difference on the taste and  smell of the finished product.  Clean feed and a clean lot can make a difference.  There is also a difference in hogs fed on an open lot (grassy) v.s. a confinement.

Corn blend with soy protein - one flavor.  Alphalfa pellets, another flavor.   Open lot with wild onions or other strong products, another.   Wood lots (acorns etc) another.  It depends on what is desired, as these also will impact the texture and fat content percentage.