Are prions in chicken? Understanding the science of avian resistance

January 12, 2026 •

3 min read

No documented cases of spontaneous prion disease have ever been reported in chicken, establishing their strong resistance. The question, "Are prions in chicken?", is a common public concern, but scientific evidence shows a powerful species barrier that protects poultry from diseases like Bovine Spongiform Encephalopathy (BSE).

Quick Summary

Chickens are highly resistant to prion diseases like BSE, supported by failed transmission experiments and genetic research showing a robust species barrier. This resistance means no public health risk is posed by prions in chicken meat.

Key Points

Genetic Resistance: The unique genetic makeup and stable structure of the chicken prion protein (PrP) provide strong resistance to misfolding.
No Reported Cases: No spontaneous or natural cases of prion disease have ever been identified in chickens, even after past potential exposure to contaminated feed.
Failed Transmission Studies: Scientific experiments demonstrated that chickens do not develop prion disease after direct exposure to high doses of the BSE agent.
Robust Species Barrier: Significant genetic differences between avian and mammalian prion proteins create a powerful species barrier that protects poultry from diseases like BSE.
Negligible Human Health Risk: Because chickens are resistant and do not harbor infectious prions, there is no known human health risk related to prion disease from consuming chicken.
Structural Stability: Unlike the flexible mammalian PrP, the chicken PrP has a stable, protease-resistant N-terminal domain that prevents disease propagation.

A significant public health concern surrounding prion diseases, also known as transmissible spongiform encephalopathies (TSEs), gained prominence during the 'mad cow disease' (BSE) crisis in the United Kingdom. Prions are abnormal, misfolded proteins that can cause fatal neurodegenerative diseases by inducing normal proteins to also misfold. While these diseases are documented in various mammals, including humans (Creutzfeldt-Jakob disease or CJD) and cattle (BSE), scientific investigation into whether chickens could also be susceptible has consistently found a powerful species barrier prevents transmission. Research into the unique biological mechanisms of avian prion protein provides reassurance regarding food safety and clears up misconceptions about whether prions can be found in chicken.

Why Chickens are Resistant to Prion Diseases

Unlike mammals, chickens possess a cellular prion protein with a distinct structure that makes it highly resistant to the pathogenic misfolding characteristic of prion diseases. This resistance is primarily rooted in fundamental genetic and structural differences between avian and mammalian prion proteins.

Key Genetic and Structural Differences

Tandem Repeat Regions: Mammalian prion protein gene contains octapeptide repeats in its N-terminal domain, associated with copper binding and flexibility. Chickens, however, have hexapeptide repeats with a different composition.
Protein Stability: The chicken prion protein's N-terminal tandem repeats form a stable, protease-resistant unit. This stability helps prevent the misfolding process.
Genetic Variation: Studies have found no single nucleotide polymorphisms in the chicken prion protein gene associated with prion disease susceptibility, unlike in mammals where such variations correlate with disease risk.

Experimental Evidence and Historical Context

During the BSE crisis, when some poultry were potentially exposed to contaminated feed, research was conducted to see if chickens could contract the disease. A study exposing domestic chickens to high doses of the BSE agent through oral and injection routes found no evidence of transmission. The chickens showed no clinical signs and post-mortem exams found no pathological evidence or disease-associated prions. This study confirmed chickens are protected from mammalian prion diseases.

Summary of Chicken Prion Resistance

Genetic Variation: Distinct characteristics in the chicken's prion protein gene, like hexapeptide tandem repeats, contribute to resistance.
Protein Stability: The chicken prion protein structure is stable and resistant to misfolding.
Experimental Confirmation: Studies exposing chickens to BSE showed no disease development.
Epidemiological Evidence: No reported natural cases of prion disease in chickens support natural resistance.

Mammalian vs. Avian Prion Protein Structure: A Comparison

Differences between susceptible mammalian and resistant chicken prion proteins are highlighted below:


Feature	Mammalian Prion Protein	Avian (Chicken) Prion Protein
Susceptibility to Misfolding	High; readily converts to pathogenic form	High resistance; stable protein structure
N-Terminal Tandem Repeats	Octapeptide repeats (PHGGGWGQ)	Hexapeptide repeats (PHNPGY)
Domain Stability	Flexible N-terminal domain	Stable, protease-resistant N-terminal domain
Copper(II) Binding	Strong binding; can destabilize protein structure	Weak or no binding; unaffected structure
Sequence Homology to Avian PrP	Low (approx. 30%)	N/A

The Role of Avian Scavengers and Prion Spread

While chickens are resistant, some avian scavengers like crows can pass infectious prions through their digestive systems, becoming passive carriers, not hosts. This means they could spread environmental contamination, but it does not mean chickens as a food source are a risk. This highlights how prions persist and the differing roles of bird species, but the fundamental genetic resistance of chickens remains unchanged.

For more information on a study about BSE transmission to chickens, see the findings in BMC Research Notes.

Conclusion

Scientific evidence from genetic analysis and experiments confirms chickens are highly resistant to prion diseases like BSE. Their unique prion protein structure creates a strong species barrier. Concerns about prions in chicken meat as a human health risk are unfounded. The biological evidence reassures that prions in chicken is a myth, not a reality.

Frequently Asked Questions

No, extensive research has proven that chickens are highly resistant to Bovine Spongiform Encephalopathy (BSE). Experiments that directly exposed chickens to the BSE agent failed to induce any disease.

The risk is considered non-existent. Since chickens are not susceptible to prion diseases and do not accumulate infectious prions, consuming chicken does not pose a prion-related health risk to humans.

Yes, chickens, like all vertebrates, have a normal, cellular prion protein ($PrP^C$). However, its unique genetic sequence and stable structure prevent it from misfolding into the pathogenic form ($PrP^{Sc}$).

Yes, prior to the implementation of strict feed bans, some poultry were fed diets containing rendered mammalian byproducts. Despite this exposure, no prion disease outbreaks were ever observed in chickens.

The chicken prion protein is fundamentally different in its amino acid sequence, particularly within its tandem repeat regions. It features hexapeptide repeats instead of the octapeptide repeats found in mammals, contributing to a more stable structure.

No spontaneous prion diseases have been reported in any avian species, suggesting a general resistance across the class. However, research indicates subtle differences in prion protein properties between species like ducks and chickens.

Since chickens do not have a pathogenic form of the prion, there is no disease to transmit. However, studies show that infectious mammalian prions can pass through the digestive systems of some scavenging birds, who act as passive carriers, not hosts.

This question is not relevant to chicken since they are resistant. However, generally speaking, infectious prions are extremely resistant to conventional cooking temperatures, and require specialized high-temperature incineration for destruction.