Avian influenza is in the same virus family as seasonal flu. Poultry has proven to be very sensitive to the virus, which results in high mortality.

The price of eggs at U.S. grocery stores has climbed to a record high, nearly doubling from a year ago, as outbreaks of bird flu have led to shortages by wiping out millions of hens.

For Brian Kreher, a fourth-generation farmer in the small town of Clarence, New York, the latest outbreak of bird flu has meant many sleepless nights. He considers his 18-acre farm one of the lucky ones.