Because of a national egg shortage, the San Antonio-based fast food chain says it will now only be serving breakfast from 5 a.m. to 9 a.m. on weekdays. The brand previously served breakfast until 11 a.m.
The national egg shortage is a result of bird flu, which NBC News reports has sickened more than 44 million chickens.
Whataburger stressed that the egg shortage is a supply issue and that consumers' food is safe.
It's unclear whether other fast food chains will be forced to follow suit.
News of Whataburger's limited breakfast is a major disappointment to fans.
@Whataburger You just lost a daily customer due to shorter breakfast hours. Went to competitor next door - no problem. Sorry!
- Rick Lawson (@rlawson330) June 1, 2015
My life is over. The world is ending. ???? https://t.co/mYMAFGUieX
- leila (@LYdrogo) June 1, 2015@Whataburger lost a loyal customer today! Breakfast ending at 9am now! #mistake #badbuisness #chickfila
- Jeremy Poe (@poej103) June 1, 2015Whataburger acknowledged customers' frustrations and is working to increase egg supply.
"We're exploring several options to add to our egg supply, including proactively engaging alternative egg suppliers," the company said in a news release. "Replacing the supply we have lost will take some time, but it is important to us to provide the highest quality food to our customers."
The company has not revealed if or when it will go back to its normal breakfast hours.