A bird flu outbreak nationwide is keeping egg prices high. As of Monday, restaurant chain Waffle House is charging 50 cents per egg to offset the cost of landing each one.

The average price for a dozen grade A large eggs has been rising since October, when the average was $3.37. As of December, it had jumped to $4.15, according to the Bureau of Labor Statistics.

On the supply end, the 30-day period ended Monday saw 79 commercial flocks and 42 backyard flocks containing over 22.7 million birds affected by the disease, according to the Agriculture Department’s Animal and Plant Health Inspection Service.

“The continuing egg shortage caused by [highly pathogenic avian influenza, or bird flu] has caused a dramatic increase in egg prices. Customers and restaurants are being forced to make difficult decisions. … We cannot predict how long this shortage will last. We are continuously monitoring egg prices and will adjust or remove the surcharge as market conditions allow,” Waffle House told The Daily Beast.

The chain says on its website that it serves 272 million eggs a year.

Birds at facilities with confirmed infections are discarded, restricting the national inventory of egg-laying hens.

Over 14 million egg layers were killed in January, according to Agriculture Department data. The culls affected 6.5% of the nationwide caged layer flock as of Jan. 1, 2.1% of the nonorganic cage-free flock and 0.1% of the organic flock.

The egg industry says that, so long as bird flu outbreaks continue, prices will remain high.

“Until we have time without a detection, unfortunately this very, very tight egg supply is going to continue,” American Egg Board CEO Emily Metz told CNN.

• Brad Matthews can be reached at bmatthews@washingtontimes.com.