Antibiotics in Chicken and Other Animals Is a Big Public Health Risk

Consumers should be wary of “antibiotic-free” claims on meat.

Closeup of broiler chicken

Explainer Health Public Health

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Animal agriculture’s widespread use of chicken antibiotics, along with the use of antibiotics in other farmed animals, contributes to the growing problem of antibiotic resistance (AMR). As the World Health Organization says, antibiotic resistance is a very serious issue, “one of the biggest threats to global health, food security, and development today.”

The discovery of antibiotics to combat bacteria and infection was one of the most significant medical advancements in human history. Yet today, humanity is threatening the efficacy of antibiotics and jeopardizing the health of our species.

Let’s take a look at the example of antibiotics in chickens in particular, and what it reveals about the problem of antibiotic use in farmed animals in general.

What Is Antibiotic Resistance?

Bacteria can become resistant to antibiotics by mutating in response to the treatment. A process of natural selection sets in; because the non-resistant strains are killed by antibiotics, the antibiotic-resistant forms of bacteria are mainly left to proliferate.

These types of resistant bacteria can be immune to treatment, making them far more dangerous when infecting the human body.

Antibiotic-resistant bugs can spread to human populations through the environment, such as through waterways and soils, and the handling of affected food products. Workers who have direct contact with farmed animals, such as veterinarians and farm workers, also face increased risk of exposure.

How Antibiotics Fed to Chicken Can Lead to Resistant Bacteria

In 2019, the WHO warned that without action, AMR could lead to 10 million annual deaths by 2050. Already, antibiotic-resistant infections make 2.8 million people ill in the U.S. each year, killing tens of thousands of people.

Consider campylobacter, a bacteria that is one of the leading global causes of gastroenteritis and diarrhea: the Centers for Disease Control and Prevention (CDC) lists campylobacter among the top five causes of foodborne illness, alongside salmonella and others.

In 2022, the Bureau of Investigative Journalism reported that U.S. companies, including poultry firms, sold tens of thousands of meat items that were contaminated with campylobacter and salmonella between 2015 and 2020. Over half of the bacteria were antibiotic-resistant.

Campylobacter infections are mostly mild, but can be deadly. Young people and elderly people, along with individuals who have vulnerable immune systems, are particularly at risk and rely on having effective antibiotics.

Furthermore, a study published in April found that some resistant bacteria are not only able to withstand antibiotics, but can also resist critical elements of humans’ natural immune system defenses. Lead researcher ​​Prof Craig MacLean explained, “This is potentially much more dangerous than resistance to antibiotics.” He continued, “It highlights the danger of indiscriminate use of antimicrobials in agriculture. We’ve accidentally ended up compromising our own immune system to get fatter chickens.”

What Does the CDC Say About Antibiotic Resistance?

AMR killed over 1.2 million people worldwide in 2019, and was associated with the deaths of many millions more.

The CDC warns that AMR “has the potential to affect people at any stage of life, as well as the healthcare, veterinary, and agriculture industries. This makes it one of the world’s most urgent public health problems.”

Why Are Chickens Given Antibiotics?

Producers have a bad habit of treating the symptoms of animal agriculture, rather than changing the conditions themselves. Administering antibiotics to farmed animals, including chickens, is mainly a way of tempering the health issues inherent in industrial farming practices.

Chickens are sometimes given antibiotics to encourage growth. Scientists discovered in the mid-20th Century that chickens fed B12 grown from antibiotic residue grew 50 percent faster. As of 2017 in the United States, the use of antibiotics to encourage growth is being limited for food-producing animals. It is prohibited in the U.S., China, the EU and the UK. However, some countries still permit antibiotic use for growth.

The second reason for antibiotic use in chickens is to keep animals healthy — or at least healthy enough to gain  weight before slaughter. Chicken antibiotics are administered because industrial chicken farms are effectively incubators for disease.  Laying hens are often crammed into small cages the size of a sheet of paper, while those raised for meat are crammed into large factories. These conditions create heat stress and other health conditions, making them breeding grounds for bacteria like salmonella.

Additionally, chickens are susceptible to catching diseases in industrial farming due to their suppressed immune systems. In nature, chicks are exposed to microbes, which builds up their antibodies and strengthens their immune system. This is not possible in the confines of industrialized farming.

Fundamentally, the administering of chicken antibiotics is done for the profit of the agricultural industry, which desires birds who grow rapidly and don’t prematurely die of disease. Antibiotics also allow farmers to keep chickens in enormous numbers — up to tens of thousands of chickens per building —  in unsanitary conditions.

Are Antibiotics Legal in Chicken?

Antibiotics are legal to use in chickens and other farmed animals in the U.S.. Analysis released in 2021 showed that around 65 percent of medically important antibiotics sold in the U.S. in 2019 were also used in non-human animals.

In 2022, researchers published an industry-supported study on antibiotic use in broiler chickens. It found that antibiotic use in various parts of the production process decreased between 2013 and 2021. This is perhaps unsurprising, considering the U.S. introduced its ban on using antibiotics for growth in 2017.

Meanwhile, a 2022 study found that the use of antibiotics that are important in human medicine has only seen a modest decline in farming since 2009. Sales of these drugs actually increased between 2017 and 2020, rising by eight percent.

Overall, around half of the antibiotics used on farms in the U.S. are medically important drugs for humans.

Does Chicken in the U.S. Contain Antibiotics?

Although the U.S. prohibited use of the drugs for growth promotion in 2017, use for disease prevention and treatment remains permissible. This means that unless chicken products state otherwise, it’s fair to assume that antibiotics have been used at some point.

Other countries, such as those within the EU, have banned the preventive use of antibiotics. Instead, farmers are supposed to limit use to animals where disease is evident.

The U.S. sets minimal withdrawal periods for antibiotic use, meaning a length of time between the last use of the drug and production of an animal product, to avoid antibiotic residues being present.

Nonetheless, antibiotic residue on meats, including chickens, is still an issue. Studies suggest this is more of a problem in poorer countries, although residues have also been found in meat in the U.S.

Does Tyson Use Antibiotics in Its Chicken?

The food giant Tyson made headlines in 2023 by announcing that it planned to change its policy on chicken antibiotics. In 2017, the company announced that the chickens in its supply chain would have “no antibiotics ever.” This will no longer be the case — or a claim they can make — following the company’s policy change.

Other large producers like Perdue Farms have a “no antibiotics ever” policy, whereas  others, such as Pilgrim’s Pride, continue to use antibiotics.

What Does Antibiotic-Free Chicken Mean?

Companies have made various claims about their chicken products; that they are “antibiotic-free,” or don’t contain antibiotics that are medically important to humans.

Broadly speaking, making such claims means that the company is committing to not giving the specified antibiotics to chickens via their feed, injection or water. However, probes have found some “antibiotic-free” claims to be questionable, and the verification system is less than robust.

In June, the U.S Department of Agriculture said it will conduct sampling for antibiotic residues in cows whose meat is marketed as “raised without antibiotics.” It’s a step in the right direction, but consumers should still be wary of companies’ marketing claims.

What Antibiotics Are Used on Chickens?

Some of the antibiotics used in chicken farming are:

Who Regulates the Administration of Chicken Antibiotics in the U.S.?

The U.S. Food and Drug Administration regulates the use of chicken antibiotics in the agricultural sector.

Multiple U.S. agencies are also involved in the U.S. National Action Plan for Combating Antibiotic-Resistant Bacteria, which has implications for the use of antibiotics in farmed animals.

How Does the FDA Regulate the Use of Poultry Antibiotics?

The FDA produces industry guidance and introduces new regulations to control the use of antibiotics, such as its 2017 ban on using antibiotics for growth. However, FDA guidance is non-binding, and the regulations contain exploitable loopholes. A2022 analysis also showed that U.S. companies are reducing antibiotic use at a slower pace than European nations, which suggests a lack of vigor in the current regulations.

The Bottom Line

In 1950, when it was first unearthed that giving chickens antibiotics would increase their growth, a reporter for Science News Letter claimed that the discovery “cast the antibiotic in a spectacular new role” for the “survival of the human race in a world of dwindling resources and expanding populations.”

As it turns out, the opposite may in fact be true, with antibiotics in farming playing a “spectacular new role” in putting human populations at severe risk.

Antibiotics are essential to human health. Continuing to use chicken antibiotics, along with administering the drugs to other farmed animals, is a recipe for a global health disaster.

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