Over the last 30 days, 151 flocks have been confirmed to have avian flu, affecting more than 23 million birds, according to the Animal Planet Health Inspection Service part of the USDA. Dr. Paul Offit, of the FDA Vaccine Advisory Committee, says people could also become sick.

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.