Disease

Beware of Poultry diseases in Summer Season

March 27, 2026
SR Publications
Dr.R.N.S.Gowda*

Former and Founding VC,KVAFSU, Bidar, Former Director, IAH&VB, Bangalore, Former Prof and University Head, Dpt. Of Pathology, Veterinary College, UAS, Bangalore)

Our country is heading into a hotter-than-normal summer for 2026. The India Meteorological Department (IMD) recently warned that most of the country will face an above-average number of heatwave days from March to May.

Summer stress is a major challenge in poultry production, especially during the summer months. It occurs when birds face difficulty in achieving a balance between body heat produced and heat lost. This imbalance can lead to several health issues and production losses.

Summer in poultry farming brings unique challenges, primarily because birds lack sweat glands and rely on respiration to cool down. High temperatures lead to Physiogical changes making your flock significantly more susceptible to both environmental stress and infectious outbreaks. 

Why Poultry is more prone to diseases in summer?

Poultry is more prone to diseases in summer primarily because high temperatures and humidity trigger a cascade of physiological and environmental changes that weaken their natural defenses. Unlike mammals, birds lack sweat glands and have feathers that trap heat, making it extremely difficult for them to cool down once environmental temperatures exceed their “comfort zone”or thermoneutral zone (typically 18°C–22°C).

Any increase in temperature brings  in Physiological Consequences

  1. Respiratory & Metabolic Strain
  2. Panting & Alkalosis: Birds rely on rapid panting to dissipate heat. This leads to an excessive loss of CO2, causing respiratory alkalosis (blood becomes too alkaline). This imbalance stresses the body and interferes with critical functions like eggshell mineralization in layers.
  3. Energy Drain: Panting and maintaining a high body temperature consume massive amounts of energy that would otherwise be used for growth or immune defense.
  • Performance Loss: Broilers see reduced body weight gain and poor meat quality (e.g., pale, soft, and exudative meat), while layers experience a drop in egg production, size, and shell strength.

2. Gut Health & “Leaky Gut”

To cool down, poultry divert blood flow away from internal organs (like the gut) to their skin and respiratory surfaces. This causes:

  • Leaky Gut: Heat stress reduces blood flow to the internal organs, causing hypoxia and oxidative stress in the intestines. This compromises the gut barrier, allowing pathogens and toxins to enter the bloodstream.
  • Intestinal Ischemia: A lack of oxygen and nutrients in the gut leads to the breakdown of the intestinal lining, a condition known as “Leaky Gut”.
  • Bacterial Translocation: Toxins and harmful bacteria (like Salmonella and E. coli) can leak from the gut into the bloodstream, causing systemic infections.
  • Dysbiosis: Heat alters the gut’s microbial balance, reducing beneficial bacteria and allowing pathogens to flourish, which often leads to Necrotic Enteritis

3. Immunosuppression (Weakened Immunity) 

Heat stress acts as a major immunosuppressant. It triggers the release of stress hormones like corticosterone, which leads to: 

  • Regression of Immune Organs: Significant shrinking of the spleen, thymus, and bursa of Fabricius, which are critical for producing white blood cells and antibodies.
  • Reduced Antibody Production: Lower levels of circulating antibodies (IgG, IgM, and IgA), making vaccinations less effective and birds more vulnerable to viral outbreaks like Newcastle Disease.
  • Cellular Damage: Heat stress causes oxidative stress, where an overproduction of free radicals damages cells, including immune cells, further reducing the bird’s ability to fight infection. 

4. Environmental Factors

  • Pathogen Proliferation: Warm, humid conditions are ideal for the rapid growth of bacteria, fungi (molds), and viruses in feed, water, and litter.
  • Poor Air Quality: Increased humidity and wet litter lead to higher ammonia levels, which irritate the respiratory tract and make birds more susceptible to respiratory diseases.

Common diseases in summer are:

  • Heat Stress/Heat Stroke: The primary issue, caused by the absence of sweat glands, leading to panting, wing lifting, reduced appetite, and death, particularly between 5 pm and 7 pm.
  • Viral Outbreaks: Immunodeficiency during heat can trigger outbreaks of Newcastle Disease (Ranikhet), Infectious Bronchitis (IB), and Fowl Pox, which is often spread by increased mosquito activity.
  • Bacterial Infections: Warm, humid conditions favor the growth of pathogens like Salmonella, Campylobacter, and Colibacillosis.
  • Necrotic Enteritis & Coccidiosis: Heat stress damages intestinal integrity and alters microbiota, fostering bacteria and protozoa, which increases susceptibility to necrotic enteritis.
  • Salmonellosis (Pullorum/Typhoid): High temperatures can exacerbate these bacterial infections.
  • Fowl Cholera: Characterized by labored breathing, diarrhea, and decreased activity.
  • Respiratory Issues: Increased dust and poor air quality in warm, humid weather can lead to sneezing and wheezing. High ammonia buildup from wet litter combined with heat can cause Chronic Respiratory Disease (CRD), leading to sneezing, rales, and swollen faces.
  • Parasite Infestations: Mites, lice, and flies thrive in summer, causing skin irritation and disease transmission. Summer heat accelerates the life cycles of mites, lice, and ticks, which can further drain a bird’s energy and immunity. Table1. Occurrence of diseases in summer.

Table 1 .common  occurrence of diseases and parasites during summer.

Sl noBacterialViralFungal Parasitic
1SalmonellaFowl PoxAspergillosisAscaridiasis
2Mycoplasma-MG,MSvvNDCandidiasisTapeworms
3ColibacillosisIB  Lice
4Infectious CoryzaILT  mites
5PasteurellosisHPAI  ticks
6CampylobacterIBD  

Preventive Management Strategies

Avoiding summer diseases in poultry requires a proactive, multi-faceted approach focusing on mitigating heat stress, which is the primary cause of immunosuppression and mortality (Colibacillosis, Coryza, Coccidiosis). Key strategies include maintaining a cool, well-ventilated environment, adjusting nutrition, ensuring constant access to cold water, and strict biosecurity.

  1. Housing & Environmental Control
  2. Ventilation: Use exhaust fans and foggers to increase air velocity. Foggers can reduce house temperatures by 5–10°C.
  3. Stocking Density: Reduce bird density by 10–20% to allow more floor space for heat dissipation.
  4. Roof Treatment: Whitewash the roof with lime to reflect solar radiation or use thatching with agricultural waste like paddy straw for insulation. 
  5. Litter Care: Maintain dry, loose litter (maximum 2 inches thick) to prevent ammonia release and bacterial flourishing.
  6. Biosecurity: Maintain strict quarantine for new birds and prohibit wild birds, which are carriers of diseases like Avian Influenza, from entering the shed.
    1. Water Management & Hygiene
  7. Water consumption can double or triple in summer, making it the primary vehicle for both cooling and potential infection. 
  • Cool Supply: Keep water temperature below 25°C. Use insulated pipelines or cover tanks with wet gunny bags to prevent heating from sunlight.
  • Sanitization: Flush lines every 48 hours with hydrogen peroxide or organic acids to remove biofilms where bacteria like E. coli thrive.
  • Supplementation: Add electrolytes (sodium, potassium, chloride) to maintain osmotic balance and Vitamin C (250–500mg/liter) to combat oxidative stress.

3Feeding Practices

  1. Digestion generates metabolic heat, which can be fatal during the hottest parts of the day. 
  • Timing: Provide 60% of the daily ration before 8:00 AM and the remaining 40% after 6:00 PM. Withdraw feed entirely between 10:00 AM and 4:00 PM.
  • Nutrient Density: Since birds eat less in heat, increase dietary energy using fats/oils (which have lower metabolic heat than grains) and boost levels of amino acids and minerals.

Additives: Include probiotics (e.g., Lactobacillus) to maintain gut health and antifungals in feed to prevent mold growth in humid conditions. 

  1. Health & Vaccination Protocols 

Heat stress causes immunosuppression, leading to increased outbreaks of Newcastle Disease (ND), Infectious Bronchitis (IB), and Infectious Bursal Disease (IBD). 

  • Vaccination Timing: Only vaccinate during the coolest hours (night or early morning) to avoid compounding heat stress.
  • Biosecurity: Maintain strict control over visitors and equipment. Ensure wild birds and rodents—which carry summer-prevalent diseases like Avian Influenza and Salmonella—cannot enter the shed.

Monitoring: Use serological tests (like ELISA) to monitor antibody titers, as they often drop during summer months. 

Conclusion: Summer poses major health risks to poultry due to intense heat stress, immunosuppression, and high pathogen growth, often causing mortality, reduced feed intake, and poor egg quality. Common threats include necrotic enteritis, coccidiosis, and infections like Salmonella and Fowl Cholera. Key management involves providing clean water, proper ventilation, and shade.