It's not as absurd as it sounds, says Robyn Metcalfe, a food historian who teaches at the University of Texas at Austin. A GPS tracker strapped to the leg of a chicken, says Metcalfe, means "that people who potentially will buy that chicken will know every step that that chicken has taken." ZhongAn Online, a Chinese insurance company, has already outfitted more than a 100,000 chickens with trackers. The sensors upload information, such as how much exercise each chicken gets and what it ate. They are also working on facial-recognition technology so that consumers can one day make sure the...