The Future of Chicken, Without Antibiotics

Human drugs have been crucial to poultry farming. So what’s replacing them?

A veterinarian holds up a chick.
A nine-day-old chick at a farm in California (Max Whittaker / Reuters)

For decades, farmers have used low doses of human antibiotics to fatten their chickens. In the future, if one company has its way, farmers will use a fungal extract originally found in a Japanese pigsty.

Welcome to poultry farming in 2018. In the past few years, with evidence linking antibiotics on animal farms to drug resistance in humans, poultry producers (Perdue, Tyson, etc.) and restaurant chains (McDonald’s, Chick-fil-A, Wendy’s, Burger King, etc.) have pledged en masse to limit antibiotics in their chicken. It’s easy to pledge, but harder to do. The shift has farmers scrambling to break their reliance on antibiotics and find new ways to help their birds grow.

Which brings us back to the pigsty fungus. Scientists at the Danish company Novozymes recently found that an enzyme in the fungus helps clear dead cells in chickens’ guts. The enzyme, which the company and its animal-nutrition partner DSM are calling Balancius, allows the birds to absorb more nutrition from food. The result, says the Novozymes vice president Lone Dybdal Nilsson, is less feed, less poop, and more chicken.

Balancius is the latest in a category of products—including probiotics, prebiotics, and essential oils—that have gained popularity with the phaseout of antibiotics. “New products are coming out every day,” says Bruce Stewart-Brown, a veterinarian and senior vice president at Perdue. Perdue began eliminating antibiotics from its chicken operations in 2002. It took the company 12 years to go all the way.

“It is tough,” says Todd Applegate, a poultry-nutrition expert at the University of Georgia. Antibiotics were a wonder supplement for farmers, and the new products just “don’t have the same range of functions that the antibiotics convey.”

After all, antibiotics helped build modern industrial chicken farming, and they’re embedded in nearly every step of the chicken-raising process. It begins before the animals even hatch. While still in the egg, they get a vaccine, and antibiotics are used to keep the injection site bacteria-free. As adults, chickens are fed low doses to enhance their growth and prevent diseases. An intestinal parasite called coccidiosis is particularly difficult to control without antibiotics. (Perdue occasionally uses antibiotics to treat flocks sick with coccidiosis, though it does not label that meat “antibiotic-free.”)

Probiotics, or beneficial bacteria, are one alternative to help with maintaining healthy gut flora in the chicken. For poultry, common probiotics include Lactobacillus, which are similar to bacteria found in yogurt and human probiotics, and Bacillus, which are soil bacteria of the sort chickens might naturally encounter if they were rooting around outdoors.

Farmers can also feed chickens prebiotics, which are carbohydrates that beneficial bacteria like to eat. Inulin extracted from chicory is one example. Essential oils from plants like oregano and thyme are also used. The oils have antibiotic properties of their own, says Applegate, and they also seem to have positive effects on the gut flora.

Perdue has tested 15 or 20 of these probiotics and prebiotics, estimates Stewart-Brown. “A lot of them don’t work very well,” he says. Or some might work in young chicks, and others only in older birds. Testing the effectiveness of new products has become a whole project on its own. Chicken producers who once had decades of experience using antibiotics are learning the process all over again with new probiotics and prebiotics.

More importantly, perhaps, elimination of antibiotics has also forced a bigger-picture rethinking of how to raise chickens. To ward off disease, producers are crowding fewer birds in a barn, letting barns stay empty for longer before introducing new chicks, and generally becoming more attuned to the welfare of their animals. The indiscriminate use of antibiotics had a way of masking poor practices, which now have to be dealt with head-on. “I believe no antibiotics has made us care for animals in a whole new way,” says Stewart-Brown.

In 2016, use of antibiotics on animal farms in the United States fell for the first time since the Food and Drug Administration began keeping track. The FDA also put a new policy into effect in 2017 that effectively ended the use of human-important antibiotics for growth enhancement. (Preventative use is still allowed under veterinary supervision.) Only one major chicken producer, Sanderson Farms, says it remains committed to the use of antibiotics—and its shareholders are pressuring the company to stop.

Feeding probiotics, essential oils, and fungal enzymes to chickens may sound a bit funny now, but in a few decades, it is likely the routine use of human antibiotics in chickens that will, in retrospect, seem unbelievable.