NEW YORK (AP) — KFC said Friday that it will stop serving chickens raised with certain antibiotics.

The fried chicken chain said the change will be completed by the end of next year at its more than 4,000 restaurants in the U.S.

KFC said is working with 2,000 farms around the country to stop using antibiotics that are used by humans. Antibiotics specific to animals may still be used to treat diseases in the chickens, KFC said.

Meat producers give animals antibiotics to make them grow faster and prevent illness, a practice that has become a public health issue. Officials have said that it can lead to germs becoming resistant to drugs, making antibiotics no longer effective in treating some illnesses in humans.

KFC’s rivals have already announced plans to curb their use of chickens raised with antibiotics. Chick-fil-A has said that by 2019 it will only serve chicken that has never been given any antibiotics. And McDonald’s Corp. has stopped using chickens raised with antibiotics important to human medicine for its McNuggets.

KFC, owned by Louisville, Kentucky-based Yum Brands Inc., said it is also in the process of removing artificial colors and flavors from certain menu items by the end of 2018.