The egg shortage that’s led to Whataburger limiting its breakfast-serving hours is also being observed by local stores.

Due to the Midwest bird flu crisis which has cut egg supplies, the fast-food chain will serve breakfast 5 a.m. to 9 a.m. weekdays, and 5 a.m. to 11 a.m. on weekends. It previously was available 12 hours a day.

The U.S. Department of Agriculture says confirmed outbreaks in the Midwest have cost chicken and turkey producers more than 44 million birds. Egg prices have soared.

Major chains such as Taco Bell and IHOP say they're monitoring the situation but haven't yet been affected.

Bob Krouse, CEO of Midwest Poultry Services, said if a company relies on a supplier that's affected by avian flu, it might have trouble finding another one. In a written statement, Whataburger said it didn't know why other restaurants haven't been affected but that it's "primary egg supplier was one of the hardest hit by this shortage."