From the air, the place where bacon comes from is a quilt of fields and woods crossed by roads and winding creeks.

On an overcast day in September, I was buzzing over eastern North Carolina's flat coastal plain in a single-prop Piper Arrow with retired riverkeeper Rick Dove and pilot Bob Epting. From an altitude of 1,200 feet (366 meters), we gazed down at the land of hogs: fields in every direction dotted with long, metal-roofed barns housing thousands of animals—and, shimmering in the faint sunlight, the pink ponds that held their waste.

The animals were destined to become honey-cured ham, bologna, smoked sausage, pulled pork, pork chops, bacon bits, and more. The meat would be shipped all over the world.

But before