Yet its unusual life had given scientists something far more valuable than eggs: a rare glimpse into how the cells of a developing bird can carry and express their own biological identity.… One autumn morning, a small roadside market in a provincial town was selling day-old chicks for almost nothing. Among the yellow, peeping chicks was one that looked slightly different. It was unusually vigorous, with long legs and a surprisingly strong appetite. While the vendor was distracted, the chick squeezed through a gap beneath a wooden crate and disappeared into the neighboring gardens. It eventually wandered into the yard of a twelve-year-old boy named Ren. Ren caught it beneath an overturned basket. “Can we keep it?” His mother hesitated. They already had a dog, and the garden was small. But Ren promised to feed it every morning and clean the coop himself. So the chick stayed. They named it Kiiro. At first, there was nothing...