The High Plains dairy complex reflects the new scale of the U.S. organic industry: It is big. The complex is home to more than 15,000 cows, making it more than 100 times the size of a typical organic herd. It is the main facility of Aurora Organic Dairy, a company that produces enough milk to supply the house brands of Walmart, Costco and other major retailers. But a closer look at Aurora and other large operations highlights critical weaknesses in the unorthodox inspection system that the Agriculture Department uses to ensure that organic" food is really organic. The critical issue is grazing. Organic dairies are required to allow the cows to graze daily throughout the growing season. The cows are supposed to be grass-fed, not confined to barns and feedlots. But during visits by The Washington Post to Aurora's High Plains complex across eight days last year, signs of grazing were sparse, at best. During most Post visits the number of cows seen on pasture numbered only in the hundreds. The milk from Aurora also indicates that its cows may not graze as required by organic rules. Testing ... by Virginia Tech scientists shows that on a key indicator of grass-feeding, the Aurora milk matched conventional milk, not organic. The inspectors who visited Aurora's High Plains dairy and certified it as "USDA Organic" ... conducted the annual audit well after grazing season, [and] would not have seen whether the cows were grazing as required, a breach of USDA inspection policy.