Lacey Kurth, a research associate, works with avian influenza test samples during testing in the real-time analytical diagnostics lab at the Iowa State University College of Veterinary Medicine in Ames, Iowa, U.S., on Friday, May 1, 2015. Another 1 million egg-laying hens in Iowa probably has succumbed to bird flu, deepening what is becoming the worst such outbreak in U.S. history and prompting the governor to declare a state of emergency.
Photographer: Daniel Acker/Bloomberg via Getty Images.