China's farmers domesticated animals many centuries before our common era, using both confined feeding techniques and managing grazing animals such as sheep and cattle on their extensive grasslands. Modern feeding and breeding techniques were introduced in the 20th century, but even at the end of the century most of China's pork, poultry, and eggs were produced by individual farm households using a mixture of traditional and modern husbandry techniques. Rural reforms initiated in the early 1980s…