Aaron Williams considered several agribusiness-related career options as he prepared to graduate from Iowa State University in late 2013. But the attraction of raising pigs independently on his home farm in Page County was just too strong.

Also, his timing was good.

His father, Bruce, was preparing to retire from feeding livestock after many years of raising pigs in a farrow-to-finish program for Niman Ranch. That created an ideal opportunity for the younger Williams to pursue his passion of caring for livestock while making a living in agriculture.

“The Niman system has really worked out well for me,” said the 27-year-old Williams, who has expanded his sow herd over time and recently added a new farrowing building to his farm just south of Villisca. “Really, I don’t think I’d be raising pigs at all if it...