Bruce Horovitz

USA TODAY

The antibiotic-free movement is invading the chicken coop.

Perdue Foods, the nation's third-largest chicken producer, on Wednesday announced that it has stopped use of human antibiotics with about 95% of its chickens — though it still will use animal antibiotics with about two-thirds of them. At the same time, Perdue will no longer use any antibiotics in its hatcheries.

Five years ago, Perdue used human antibiotics with 100% of its chickens.

The privately held food giant, whose combined meat and grain sales will top $7 billion this year, still will use human antibiotics with about 5% of chickens — but only for a few days when prescribed by a veterinarian for a specific problem, the company says.

"This is a big deal," says CEO Jim Perdue, the grandson of the company's founder, in an interview with USA TODAY. "We listen to consumers."

He says it's one of the biggest moves the 94-year-old company has made since it pioneered brand advertising for chicken — once viewed as a commodity product — more than 40 years ago.

This evolution away from human antibiotics has taken place over 12 years, says Jim Perdue, and the company's last hatchery that used human antibiotics stopped this summer. The company declined to say where that hatchery is located.

At least one food safety watchdog applauded Perdue's move to limit use of antibiotics.

"The amount of antibiotics used on the farm is simply not sustainable if we want to preserve their uses in human medicine," says Caroline Smith DeWaal, food safety director at the Center for Science in the Public Interest. "I hope Perdue's actions foreshadow changes across the industry."

Outside of Perdue's specific organic and no-antibiotics-ever products, its chickens generally are treated with an animal-only antibiotic for the prevention of common illnesses.

Increasing public demand for antibiotic-free foods has greatly affected antibiotic use in recent years. The Chipotle and Panera chains have been using antibiotic-free chicken for some time. And earlier this year, Chick-fil-A announced it would have only chicken raised without antibiotics in its stores within five years.

Antibiotic-free chicken now is believed to account for about 10% of the estimated $10 billion that consumers spent on fresh chicken in 2013. Along with organic chicken, it ranks among the industry's fastest-growing sectors. Beyond a strong push from consumers and food safety advocates, the Food and Drug Administration also has been coaxing food companies to migrate away from human antibiotics.

Perdue's program began in 2002, and in 2005 it phased out the use of specific medically important antibiotics in its feeds, including fluoroquinolones, four years before the FDA banned their use in animal agriculture. By 2007, it had removed all human antibiotics from its feed. In 2011, it acquired Coleman Natural Foods, adding organic chicken. And now, it has removed all antibiotics from its hatcheries.

"This will help the industry move forward," says Jim Perdue. "There's no law that you have to do this. We did it voluntarily."