More than 20 million egg-laying chickens in the U.S. died last quarter because of bird flu, data from the U.S. Department of Agriculture shows, marking the worst toll inflicted on America's egg supply since the outbreak began.

Experts with the Alabama Poultry and Egg Association said, there are several reasons as to why egg production is down, but the main reason is an outbreak of the bird flu. Experts say over the last two to three years, several outbreaks have impacted egg farms all over the U.S.