The world’s largest retailer is muscling in on one of the fastest growing segments of American agriculture - local food. Walmart says 11 percent of the produce sold in its stores nationwide comes from local farms. That’s up from 4 percent two years ago. There’s no doubt this move has shaken up the food supply chain. But as Abbie Fentress Swanson reports for Harvest Public Media, small family farms aren’t necessarily seeing the benefits.