KFC is making a big change to its menu, one that investors, customers, and public health advocates have been calling for. This morning, the chicken chain announced it will soon stop serving chickens raised on antibiotics that are medically important to human beings.

For livestock farmers, these antibiotics can help produce chickens that yield more meat. Unfortunately, the continuous low-dose use of antibiotics also contributes to the development of antibiotic resistant bacteria, rendering these very drugs less-effective (or useless) for treatment of actual disease.

In recent years, a growing number of restaurants have realized that this risk is too big a price to pay for heavier chickens. McDonald’s, Wendy’s, Chick fil-A — even KFC’s corporate cousins at Taco Bell and Pizza Hut — have all already made some commitment to sourcing chickens that are raised with fewer, or no, antibiotics.

Yet in a recent report card on restaurants’ antibiotics policies, KFC was one of 16 chains that scored a failing grade.

This morning’s announcement from KFC acknowledges that the threat of antibiotic resistance is a “rising public health concern in the U.S.” The company says that all of the chicken sold in its U.S. locations will be raised without these controversial drugs by the end of 2018.

Earlier this year, our colleagues at Consumers Union gathered more than 125,000 signatures on a petition calling on KFC and others to finally adopt policies reducing their use of antibiotics. Today, CU is applauding KFC’s decision, calling it “chicken done right.”

“Antibiotics should only be used to treat disease and not wasted on healthy livestock to make them grow faster or survive filthy conditions on factory farms,” says Jean Halloran, Director of Food Policy Initiatives for CU. “It’s time for all fast food restaurants to help ensure antibiotics keep working by rejecting meat and poultry suppliers who misuse these vital drugs.”

For poultry producers who supply KFC, the restaurant says it will require that their entire flock is antibiotic-free, even if KFC only intends to purchase a portion of that flock. As large buyers like KFC increase their demand for drug-free birds, the hope is that more farmers will shift away from overusing antibiotics.

KFC contends this is the first time a major fast food chain has pledged to go antibiotic-free for bone-in chicken. While several fast food restaurants have agreed to use antibiotic-free chicken, it has largely been limited to boneless chicken.

For example, Papa John’s committed to going drug-free for the chicken it uses for pizza toppings and its “chicken poppers,” but not for its wings. It’s the same story at Pizza Hut, where the chain only committed to tweaking the chicken “on its pizzas.”

KFC competitor Popeyes has a publicly available animal welfare policy, but it does not directly address antibiotics. We’ve reached out to Popeyes for comment on this morning’s announcement and will update if we receive a response.

Antibiotics used on farm animals account for the overwhelming majority of all antibiotics sold in the U.S., and sales have continued to increase even after drug companies volunteered to stop marketing these drugs for growth-promotion purposes.

Reducing antibiotic overuse in chickens is important, but only represents one facet of the issue. Fast food chains are already feeling the pressure to curb antibiotics in the beef and pork they buy, but that change — if it happens — will take more time. A chicken now reaches market weight in less than two months, while beef cattle may need up to two years.

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