The Cape Fear River runs through Bladen County, North Carolina, population 33,000. On its western bank, in the town of Tar Heel, sits the largest slaughterhouse in the world. Deep below the slaughterhouse, one may find the arrowheads of Siouan-speaking peoples who roamed there for a millennium. Nearer the surface is evidence of slaves who labored there for a century. And now, the slaughterhouse kills the population of Bladen County, in hogs, every...