Chickens in a futuristic farm, symbolizing genetic resilience.

Can Chicken Genes Beat the Heat? Exploring Genetic Resistance to Heat and Disease

Soraya Malik monogram
Soraya Malik in Science & Nature October 2026 • 4 min read.

"New research identifies key genes that could help chickens thrive in challenging environments, offering a path to improved poultry production and global food security."


Newcastle disease remains a significant threat to poultry farming, especially in areas with limited resources. In these regions, chickens often face multiple challenges, including heat stress, which can weaken their immune systems and reduce productivity. Finding ways to help chickens withstand these combined pressures is crucial for food security and economic stability.

Traditionally, selective breeding has been used to improve poultry traits, but breeding for disease resistance and heat tolerance is complex. It requires facing biosafety concerns, the potential for animal welfare issues, and high costs. Identifying the specific genetic factors that influence resilience can greatly speed up the breeding process.

A recent study has identified genes and genetic variations (haplotypes) that affect how chickens respond to both heat and Newcastle disease. This opens new avenues for developing chickens that are genetically predisposed to perform well under harsh conditions, ultimately boosting food production and livelihoods in vulnerable communities.

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Chicken's Global Importance

The chicken, Gallus gallus domesticus, is the domesticated form of the red junglefowl and was first domesticated around 8,000 years ago. It is among the world's most common and widespread domesticated animals, raised primarily for meat and eggs. Chicken is also the most common type of poultry and the second most consumed meat globally after pork, partly because it is relatively easy and inexpensive to raise compared with cattle or pigs. These sources establish chicken's broad importance, but they do not provide statistics on genetic heat or disease resistance.

Established Breeds and Uses

Britannica describes chickens as medium-sized poultry represented by more than 60 breeds. These breeds are primarily descended from the wild red jungle fowl, Gallus gallus, and chickens are raised worldwide for meat and eggs. This established classification and production framework provides context for studying chicken traits, but the source does not specify methods for breeding heat or disease resistance or assess their limitations.

Domestication Origins

The history of domestic chickens is generally understood to begin with the domestication of red-junglefowl-like birds. The available material suggests a long development from wild birds to animals raised for meat and eggs. It does not provide enough detail to identify particular milestones, foundational discoveries, or the historical development of genetic resistance to heat and disease.

Key Genes for Heat and Disease Resistance: What Did the Researchers Discover?

Chickens in a futuristic farm, symbolizing genetic resilience.

Researchers investigated specific genes known to be involved in immune responses, stress responses, and heat tolerance. These included TLR3, TLR7, MX, MHC-B, IFI27L2, SLC5A1, HSPB1, HSPA2, HSPA8, IFRD1, IL18R1, IL1R1, AP2A2, and TOLLIP. They studied a commercial egg-laying line of chickens, exposing half the birds to high temperatures before challenging them with Newcastle disease virus (NDV).

Throughout the study, scientists measured various traits related to heat and NDV responses. They then analyzed the chickens' DNA to identify single nucleotide polymorphisms (SNPs) within the target genes and determined the unique haplotypes. The team then examined how these gene haplotypes affected the chickens' responses to both NDV and heat stress.

Here's a breakdown of the key findings:
  • Haplotype Effects: The study identified seventeen significant haplotype effects across seven genes related to response to NDV or heat + NDV.
  • Identified Genes: Genes identified included TLR7, MX, IFI27L2, SLC5A1, HSPA2, IFRD1, IL1R1.
  • Phenotypes Observed: Researchers observed that these genes affected seven phenotypes, which included growth rate post-NDV, viral load 6 dpi, antibody 10 dpi, BE, HCO3, TCO2, PH.
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Evidence Still Limited

The available source material does not identify a specific recent study or review of chicken genes associated with heat or disease resistance. Any conclusions about current genetic research would therefore need to be treated cautiously here. More specialized scientific sources would be needed to evaluate findings, methods, and the strength of the evidence.

Unresolved Limitations

The supplied material does not document a particular breeding failure, rejected genetic strategy, or counterargument concerning heat or disease resistance. It therefore cannot establish whether proposed genetic approaches consistently succeed or fail. Claims about trade-offs, unintended effects, or limits would require evidence from studies focused on those issues.

A Broad Production Comparison

The available sources support a broad comparison between chickens and larger livestock in terms of production practicality. Chicken meat and eggs are described as relatively easy and inexpensive to produce compared with products from cattle or pigs. The material does not compare chicken breeds or species by genetic heat tolerance, disease resistance, or performance under defined environmental conditions.

The results pinpointed specific genetic variants linked to improved responses to heat and/or NDV. For instance, IFI27L2 showed a consistent effect on antibody production in NDV-challenged chickens. SLC5A1 was associated with viral load, while IFRD1 and HSPA2 affected growth rate post-NDV challenge. Furthermore, HSPA2, MX, IL1RL1 and TLR7 all had significant effects on various blood components under heat and NDV stress.

Looking Ahead: Breeding for Resilience

These findings offer valuable insights for breeding chickens that can thrive even when faced with disease and heat stress. By targeting specific genetic variants, breeders can develop more resilient and productive poultry, especially benefiting farmers in resource-limited regions. This approach could significantly enhance food security and improve livelihoods in communities that depend on poultry farming.

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What the Evidence Shows

The supplied evidence establishes chicken's long domestication history, worldwide distribution, and importance as a source of meat and eggs. It also places modern chickens within the broader lineage of red junglefowl and recognized breeds. It does not support an expert judgment about whether chicken genes can reliably overcome heat stress or disease.

Questions for Future Research

Future work could examine how particular chicken breeds perform under heat and disease pressure, but the available material does not identify specific genes, breeding programs, or research targets. Any forecast about genetic resistance would therefore be provisional. Stronger conclusions would require clearly documented experiments and comparisons across environments and breeds.

Global Production Context

Chickens are raised worldwide and serve major food, economic, and household roles through meat and egg production. Their widespread use means that environmental and health challenges could have broad consequences, although the supplied sources do not quantify those effects. The material also does not establish how production systems respond to heat or disease.

Food and Livelihood Relevance

People keep chickens primarily for meat and eggs, and chicken has become prevalent in many cuisines because it is comparatively inexpensive and easy to raise. Chickens are also kept as pets, showing that their significance extends beyond food production. The supplied sources do not provide direct evidence about how genetic heat or disease resistance affects farmers, consumers, or animal welfare.

How heat-stress comparisons vary across chickens

For Thai native chickens, a temperature-humidity index of 74 marked the point at which egg production began to decline. That threshold describes a different population and outcome from the article’s gene associations.[1]

A genome-wide comparison across a broad thermal gradient identified candidate heat-tolerance genes and pathways as convergent signals. This is a different kind of evidence from associations between selected gene haplotypes and measured responses.[2]

What the reported heat-stress figures measure

  • 32.6%Under chronic heat stress, broilers’ body weight was 32.6% lower, feed conversion ratio was 25.6% higher, and feed intake was 16.4% lower. The comparison covered birds exposed from 1 to 42 days of age; the percentages describe changes relative to the study’s comparison conditions.[3]
  • 14%In the shorter exposure, feed intake was 14% lower in younger birds exposed from 2 to 4 weeks of age. This is a separate comparison from the chronic-exposure figures, not an additional change to combine with them.[3]
  • 0.32For birds exposed only to Newcastle disease virus, reported heritability estimates were 0.32 for viral titer at 2 days post-infection, 0.18 at 6 days, and 0.24 for antibody titer at 10 days. These values provide an infection-only comparison for the same line of birds.[4]
  • 34A tropical-chicken selection scan found 34 genes with signatures of positive selection. This count refers to selection signals, not a count of genes proven to cause heat tolerance.[5]

Reading the genetic and physiological evidence

Heat stress is not only a production challenge: it can disrupt immune, endocrine, respiratory, and electrolyte regulation. That broader physiological picture helps explain why heat and disease responses may be linked, without showing that a particular genetic marker prevents those disruptions.[5]

The evidence also cautions against treating production traits as interchangeable: estimates of genetic correlation suggest that selecting for faster growth could be associated with lower heat tolerance. A favorable result for one trait therefore does not automatically imply resilience under heat.[6]

What comparisons could clarify chicken heat resilience

  • How consistently do candidate genes and pathways associated with heat response appear across populations and thermal conditions? The cited genome-wide comparison spans a broad heat-index gradient, while other findings concern particular chicken groups or exposures.[2] [5]
  • Would selecting for faster growth change heat resilience in the same way across chicken types and sexes? The reported growth response varied by group and sex, and the genetic-correlation finding points to a possible trade-off.[6]
  • How well do infection-only genetic estimates predict responses when heat and Newcastle disease occur together? The infection-only estimates offer a comparator, but do not resolve combined-stress performance.[4]

Terms for interpreting heat-response research

Calcium signaling
A pathway linking heat-sensing channels, calcium regulation, and downstream signaling.[2]

Sources

  1. The genetic impact of heat stress on the egg production of Thai native chickens (Pradu Hang dum) (pmc.ncbi.nlm.nih.gov)
  2. Whole genome analysis of selection associated with resistance to heat stress in chickens (pmc.ncbi.nlm.nih.gov)
  3. Identification of quantitative trait loci for body temperature, body weight, breast yield, and digestibility in an advanced intercross line of chickens under heat stress (link.springer.com)
  4. Genetics and Genomic Regions Affecting Response to Newcastle Disease Virus Infection under Heat Stress in Layer Chickens (pmc.ncbi.nlm.nih.gov)
  5. Genome-wide scan for selection signatures and genes related to heat tolerance in domestic chickens in the tropical and temperate regions in Asia (pmc.ncbi.nlm.nih.gov)
  6. Genetic Effect and Growth Curve Parameter Estimation under Heat Stress in Slow-Growing Thai Native Chickens (pmc.ncbi.nlm.nih.gov)

About this Article -

Written with AI assistance from published research, and reviewed by the Mystum team. See our About page for more information.

Everything You Need To Know

1

What is Newcastle disease, and why is it such a concern for poultry farming?

Newcastle disease is a highly contagious and devastating viral disease that affects poultry. It poses a significant threat to poultry farming, especially in regions with limited resources, because it can cause high mortality rates and reduced egg production. Efforts to develop chickens genetically resistant to Newcastle disease are crucial for global food security, particularly in vulnerable communities that rely on poultry for sustenance and income. The impact of Newcastle disease extends beyond just the chickens themselves; it affects the livelihoods of farmers and the availability of a vital food source.

2

What specific genes did the study focus on, and what was the purpose of examining them?

The study focused on identifying specific genes and genetic variations, known as haplotypes, that influence how chickens respond to both heat stress and Newcastle disease. Researchers investigated genes involved in immune responses (such as TLR3, TLR7, MX, MHC-B, IFI27L2, IL1R1, IL18R1, and TOLLIP), stress responses (like IFRD1), and heat tolerance (including SLC5A1, HSPB1, HSPA2, and HSPA8). They pinpointed genetic variants, called single nucleotide polymorphisms (SNPs), within these genes and examined how different gene haplotypes affected the chickens' ability to withstand heat and resist the Newcastle disease virus (NDV). This is significant because understanding these genetic links allows for targeted breeding programs to enhance resilience in chickens.

3

What were the key findings regarding the effects of specific genes on Newcastle disease and heat stress responses?

Researchers discovered that specific haplotypes within certain genes had significant effects on the chickens' responses to Newcastle disease and heat stress. For instance, IFI27L2 consistently affected antibody production in chickens challenged with NDV, indicating its role in disease resistance. SLC5A1 was associated with viral load, suggesting its influence on controlling the virus's spread within the chicken. Additionally, IFRD1 and HSPA2 impacted growth rate post-NDV challenge, highlighting their importance in recovery from the disease. Furthermore, HSPA2, MX, IL1RL1 and TLR7 all had significant effects on various blood components under heat and NDV stress, demonstrating the interconnectedness of the response to heat and NDV.

4

What is selective breeding, and how can the study's findings improve selective breeding for chickens?

Selective breeding involves choosing chickens with desirable traits, such as disease resistance or heat tolerance, and breeding them to pass on those traits to their offspring. This process has been used traditionally to improve poultry. The identification of specific genetic factors influencing resilience can greatly accelerate the breeding process. Instead of relying solely on observable traits, breeders can now target specific genetic variants (SNPs) to develop chickens that are genetically predisposed to perform well under harsh conditions. This precision breeding can lead to faster and more effective improvements in poultry resilience.

5

How can the results of this research be used to improve poultry farming and food security?

The findings can be used to breed chickens that are more resilient to heat stress and Newcastle disease. By targeting specific genetic variants, breeders can develop poultry that are genetically predisposed to thrive even when faced with challenging environmental conditions and disease outbreaks. This approach has the potential to significantly enhance food security and improve the livelihoods of farmers in resource-limited regions, who often depend on poultry farming as a primary source of income and sustenance. This targeted breeding offers a sustainable solution for increasing poultry production in areas where heat and disease pose significant constraints.

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