The pig farmers are three bootleggers whom Rocky encounters in "Rumrunner". Based on dialog it is clear that they have had prior run-ins. In "Hydrophoby" one of the farmers is identified as Avril. In "Sunshine" another one of the farmers is addressed as Emery.
After confronting Rocky in "Rumrunner", the farmers abduct him in "Hydrophoby" and place him in the back of their truck with "Frothy", a rabid pig that Avril was forced to shoot. In the farmers pin Rocky to a set of railroad tracks by nailing down his tie.