Between 2013 and 2017, a drastic shift occurred in the US poultry industry’s on-farm antibiotic use. According to a research study, “Antimicrobial Use in Poultry, 2013-2017 Report,” led by Randall Singer, DVM, Ph.D., of Mindwalk Consulting Group LLC, and funded through a contract with the US Dept. of Agriculture and the US Poultry & Egg Association, the percentage of broiler chickens receiving antibiotics in US hatcheries decreased from 93 percent to 17 percent. Additionally, according to the National Chicken Council, more than 50 percent of US broiler chickens produced today have never received antibiotics.

“Seventy to 80 percent of what I’d call the quick-serve restaurant bird is no antibiotics ever (NAE),” says Todd Applegate, Ph.D., head of the Dept. of Poultry Science and professor at the Univ. of Georgia. “Roaster birds, those going to market at 56 days of age or older are a much lower percentage, maybe about 20 percent. So, across all body weight categories we’re sitting at about 50 to 60 percent of the market today as NAE. It’s a big number and most of that transition has occurred over the past three to four years. It hasn’t been very long, which has been amazing to see.”

Consumers driven by a new-found interest in what goes on at the farm level of food production and a desire to purchase food derived from humanely raised and treated animals have been the catalyst of the change in the production of NAE poultry. While processors understand the need to keep animals healthy, as well as a general lack of knowledge on the part of the public regarding livestock production, they still must listen to the demands of consumers. Processors must balance consumer demand, animal well-being, food safety and profit margin to stay in business and feed a growing population.

The industry shows strong commitment to NAE poultry and continues to work across all segments to make production and processing in the channel as safe and humane as possible. The academic community has joined industry and the regulatory branch in the effort and uses science as its primary tool in moving NAE in the right direction with a focus on the effect on birds and alternatives to keep them healthy.

Chick-fil-A announced in September 2019 it reached the goal of serving NAE chicken in all 2,400-plus of its US restaurants.


Professor of Poultry Science at Univ. of Georgia, Manpreet Singh, Ph.D., says a disconnect exists around antibiotics used on animals for food and the effects those antibiotics do or do not have on humans. The lack of evidence, research and traceability on both the human and animal side create a void.

The popular belief is that when any animal, not just poultry, is treated with antibiotics and has pathogenic organisms in its system, the organisms get exposed to sublethal levels of the antibiotic. This creates a resistance in the organism. The idea then becomes a human sick from Salmonella, or some similar organism, cannot be effectively treated with certain antibiotics because the organism has built up resistance.

“That is one of things which is, I guess, driving a lot of these changes,” Singh says. “But at the same time, it is prudent for us to be judiciously using antibiotics and that’s why the companies are also offering these [NAE] practices.”

Singh adds that the antibiotics used for food animals today and the antibiotics used for sick humans are not the same antibiotics, and he adds resistance to antibiotics is not exclusive to food animals passing on antibiotic resistance. The pathogens do not necessarily always come from the birds. Pathogens exist everywhere, and science has not yet confirmed whether giving food animals antibiotics causes resistance in organisms.

“There are no conclusions. No one can strongly say, but there’s a lot of push from regulatory and funding agencies to provide funding so we can do the research to find out what is truly causing it [antibiotic resistance] and how we can mitigate that.”

Applegate agrees, “Our knowledge on drug resistance and microbes taking on drug resistance is a very complex science.”

The situation

According to Applegate, one of the biggest challenges producers face when moving from the use of sub-therapeutic antibiotics to an NAE program is coccidiosis. Coccidiosis occurs when pathogenic agents rapidly build up in the host. In poultry, these agents mostly belong to the genus Eimeria.

“With the NAE programs, because we don’t have as many tools to handle coccidiosis and resistance that might build to certain coccidiostats [agents inhibiting reproduction and development of Eimeria], we tend to see more necrotic enteritis occurring in these birds,” Applegate says.

Singh’s research focuses on comparing farms that use antibiotics (for health, not growth promotion) to those that don’t.

“We’re trying to look at the impact of not having antibiotics in the gut of the chicken,” Singh says, “and specifically are there implications on foodborne pathogens shedding or being present in the birds or on the finished product? Which in this case will be a processed and dressed whole bird.”

According to Applegate, when the birds do contract necrotic enteritis, between 17 and 24 days of age a period of mortality will probably occur. Some birds will suffer, some might die, others will take longer to hit target bodyweight, and as with any population, bird-to-bird responses will vary. Processors will usually still take them into the facility for processing. Different processors and producers will handle the situation differently.

“If they’re going to still label it as NAE, then they won’t treat the flock,” Applegate says. “They’ll just let them ride it out, so to speak. Or they may come in and treat, but then they cannot market that bird as NAE.”

To make the life of NAE birds pleasant and healthy, Singh and Applegate both agree that gut health of the bird is the focus. The speed at which NAE poultry has increased through the marketplace leaves scientists still searching for concrete evidence and results in terms of what it means not to treat birds with antibiotics, and ultimately solutions to maintain healthy flocks.

The use of antibiotics potentially changes the gut flora, and consequently, could affect the gut health.

“How does that flora change, and how does that impact the prevalence of pathogenic organisms?” Singh asks. “Those are the answers we’re trying to find through this research.”

Applegate agrees, “I’m always thinking about that bird and trying to make sure that we’re providing the best environment we can and taking care of it the best we can,” he says. “Inherently it has caused some issues with gut health, so we’re trying to find additional strategies to maintain gut health.”

Once a bird receives antibiotics, it cannot be marketed as NAE.

The solutions

Consumer demand for NAE poultry from both retailers and foodservice operators continues to rise, and producers and processors continue to oblige. This means the poultry industry must face the challenge and keep birds healthy without using antibiotics.

One strategy poultry producers use involves giving birds a little more space during grow out. Also, producers might increase the downtime between one flock going to processing and another coming into the house. More downtime between flocks equates to lower microbial loads and pressure.

“Typically, you were trying a minimum of 10 days in the conventional program,” Applegate says. “You may increase that to 14 to 21 days in between flocks. In that little bit of additional time, hopefully the microbial load will go down on that farm.”

Applegate adds different litter management techniques that can sometimes reduce the microbial load further. However, these approaches do mean less birds raised and processed throughout a calendar year, which tends to put a financial strain on both producers and processors.

“I think a lot of the industry to cope even further, now focuses more on the breeder’s health program and the cleanliness of that hatching egg going into the hatchery and the hygiene of the hatchery itself,” Applegate says.

Another tack the poultry industry has begun to pursue for the gut health of its birds is reminiscent of doctors suggesting humans using antibiotics eat some yogurt to balance out the gut flora and overall gut health.

“It’s the same thing in poultry,” Singh says. “They’re trying to use probiotics and looking at how they can alter the gut flora, using probiotics to mitigate the use of antibiotics. Because then you can heal the gut up with the good bacteria and prevent any of the bad bacteria from colonizing in the gut.”

Singh adds that opinions on NAE and methods to increase the health in NAE birds, and especially antibiotic resistance, will vary among all involved.

“If I ask a veterinarian their opinion, obviously if a bird is sick and needs to be treated, you’ve got to treat it with antibiotics. But at the same time, when we treat them, they need to be treated with the right dose,” he says. “If we are doing that, then those birds should be separated, or somehow not be allowed to come in contact with the other birds, so they don’t pass along any of that resistance, if in fact it’s possible for them to pass on that resistance. It becomes a very dual-edged opinion, and it can both support and not support.”