This 5-minute PBS video explains how chickens are farmed today. To survive, chicken farmers have few options; the majority wind up signing contracts with Big Chicken corporations like Tyson and Purdue. The corporations own the chickens, and the farmers are left with their “litter” — urine and manure. And therein lies the problem: What to do with tons of manure? In the U.S. south, where tens of millions of chickens are raised, too much of their “litter” winds up in the Chesapeake Bay.