Chick-fil-A is reversing course on a decade-old policy to only serve chicken that is free of antibiotics.

The company will start to loosen its purchasing standards for chicken this spring, allowing for animal antibiotics in cases where poultry become sick. The new "No Antibiotics Important To Human Medicine" policy clarifies the chain won’t use medicines to treat people.

Chick-fil-A said on its website that the shift from a "no antibiotics ever" policy is necessary "to maintain supply of the high-quality chicken you expect from us." The restaurant chain announced its far-reaching antibiotics ban in 2014.

A company spokesperson added it's become more difficult to procure large amounts of antibiotic-free chicken, according to a statement to media outlets including the New York Times.

"As we looked to the future, the availability of high-quality chicken that meets our rigid standards became a concern," Chick-fil-A said.

The company didn’t immediately respond to a request for comment, and didn’t specify in its announcement what kind of supply headwinds it anticipates for antibiotic-free birds. Last year, major poultry-producing states struggled with bird flu outbreaks, though it has largely affected egg production.

Antibiotics are commonly used in livestock production to prevent disease or to fatten up animals prior to slaughter. The Food and Drug Administration began cracking down on the use of some drugs in 2013 after finding they could contribute to treatment-resistant bacterial infections in people.

Last year, chicken processing giant Tyson Foods announced it would also move away from a “no antibiotics ever" pledge. In 2022, Chick-Fil-A settled an antitrust lawsuit with Tyson that claimed the chicken processor conspired to drive up prices shortly after the restaurant chain first announced its antibiotics-free policy.