To trace Zeller Mania back to its origins, you have to start with pigs—lots of pigs. And some cows, beans and corn. You have to travel deeper into the heartland, where the skyscrapers and asphalt jungles of America fade away into swaying fields of green and golden-brown. You have to go to Springville, Iowa (pop. 1,074). That’s where Steve and Lorri, the Zeller brothers’ parents, grew up.