After a bird flu outbreak tore through Midwestern barns, which led to 18 millions hens being killed and a spike in egg prices, the Department of Agriculture didn’t investigate whether the virus was airborne. But ProPublica did. Experts say ProPublica’s analysis offers a plausible explanation for how the wind could have helped spread the virus, exposing a flaw in the USDA’s playbook to fight it. To combat bird flu spread, other countries have authorized poultry vaccines, but the U.S. has held off amid political and economic opposition. Reporter Nat Lash breaks down his investigation into the wind trail no one is talking about. #BirdFlu #airborne #eggs