An epidemic is moving across the United States. It has invaded 35 states and sickened 324 people, including 88 children. It has put 66 people into hospitals, and one of the sick people has died. And the Centers for Disease Control and Prevention, responding as it always does to outbreaks that menace Americans, is struggling with how to stop its advance—because the things causing the epidemic are widely distributed across the country, come from many places, and are hard to trace back to their source.

And also, are super-cute. The cause is backyard chickens.

Since January, and continuing into June, there have been seven separate outbreaks of Salmonella—each caused by a different strain of the bacterium and each stretching over multiple states, from 16