Balancing Air Quality in Poultry Houses: Tackling Ammonia and Humidity for Health and Productivity

Dr. Pawar Rutik Namdev1 (MVSc Scholar), Dr. Shipra Tiwari1 (MVSc Scholar),
Dr. Mahendra Kumar Patel1 (Ph.D Scholar)
1College of Veterinary Science and Animal Husbandry, DUVASU Mathura (281001), India

Abstract
The environment within poultry houses plays a decisive role in the overall health, performance, and welfare of birds. Among various factors, the concentration of ammonia (NH₃) and the level of relative humidity (RH) are the most critical. Ammonia, released from the microbial breakdown of waste, and excessive humidity, which influences litter moisture, often work together to create poor air quality. This review highlights how these two factors are produced, their combined impact on broilers and layers, and outlines practical approaches for monitoring and management to maintain profitability and bird well-being.

1. Introduction
For poultry farmers, achieving optimal productivity requires not just good feed and genetics, but also maintaining a favorable environment inside the house. Air quality, ventilation, and litter condition all directly affect flock health. Ammonia gas and humidity levels are particularly important, as they can significantly influence bird growth, egg production, immune strength, and overall welfare. Excessive ammonia harms the respiratory tract, reduces feed intake, and lowers growth efficiency, while uncontrolled humidity leads to wet litter, higher ammonia emissions, and disease outbreaks. To ensure healthy flocks, ammonia should ideally be kept below 20–25 ppm and RH within 50–70%.

2. How Ammonia and Humidity Build Up
2.1 Generation of Ammonia
Ammonia is created naturally when uric acid in droppings is decomposed by bacteria. The process is intensified under warm, moist, and alkaline conditions. The type of litter material, stocking density, feed composition (especially protein levels), and frequency of manure removal all influence ammonia levels. Houses with poor cleaning routines or high moisture accumulation often experience higher NH₃ concentrations.

2.2 Role of Humidity
Humidity directly controls litter moisture content. High RH slows the evaporation of water from bedding, resulting in wet litter that promotes microbial activity and ammonia release. Conversely, very low RH increases dust particles in the air, which irritates the birds’ airways. Thus, moisture management is closely tied to controlling ammonia levels.

3. Impacts on Bird Health and Physiology
3.1 Respiratory Effects
Ammonia acts as a strong irritant to the respiratory tract. Continuous exposure damages the trachea and air sacs, reducing the ability of cilia to filter pathogens. Birds exposed to more than 20–25 ppm are more prone to respiratory diseases such as Newcastle, bronchitis, and Mycoplasma infections. Vaccination responses also tend to decline.

3.2 Eye and Skin Irritation
Chronic exposure to ammonia causes conjunctivitis, watery eyes, and corneal damage. High RH contributes to wet litter that leads to footpad dermatitis, hock burns, and breast blisters—all of which compromise welfare and reduce carcass quality at processing.

3.3 Growth and Feed Efficiency
High levels of ammonia reduce appetite, slow weight gain, and impair feed conversion. Even a small increase in feed conversion ratio (FCR) significantly raises production costs, especially in large flocks. Performance losses become severe when ammonia concentrations exceed 50 ppm for prolonged periods.

3.4 Immunity
Birds raised in poor air quality often show weaker immune responses. Prolonged exposure to ammonia not only stresses birds but also reduces antibody production after vaccination, leaving them vulnerable to disease outbreaks.

3.5 Egg Production
In layer flocks, poor litter conditions and elevated ammonia cause stress, leading to reduced laying rates, smaller egg size, and poor shell quality. Mortality may also rise due to an increased risk of secondary infections.

4. The Combined Impact of Ammonia and Humidity
Although ammonia and humidity can each harm poultry, their combination is especially damaging. High RH makes litter wetter, which in turn boosts ammonia emissions. Humid air also traps ammonia at bird level, ensuring birds inhale more of it. Together, these conditions encourage respiratory infections, coccidiosis outbreaks, poor weight gain, higher mortality, and overall production losses.

5. Monitoring Levels
5.1 Threshold Values
Ammonia: Should remain below 20–25 ppm (ideally closer to 10 ppm). Birds show signs of irritation even at levels humans may not detect by smell.

Relative Humidity: Best maintained between 50–70%. RH above 75% promotes wet litter, while RH below 40% leads to dust and dehydration.

5.2 Measurement Tools
Ammonia: Can be monitored using portable gas detectors, color tubes, or continuous electronic sensors.
Humidity: Inexpensive hygrometers placed at bird height provide reliable readings and are often integrated into automatic ventilation systems.

6. Strategies for Control
6.1 Ventilation
Proper ventilation ensures air exchange, dilutes gases, and removes excess moisture.

In cold weather: minimum ventilation prevents humidity build-up without chilling the birds. fans and circulation systems increase air movement and reduce heat stress.

6.2 Litter Management
Maintaining dry litter is essential. Turning litter, replacing wet spots, using absorbent bedding materials, and preventing drinker leaks are key practices. Chemical litter amendments such as alum or sodium bisulfate can reduce pH, minimizing ammonia release.

6.3 Nutrition
Adjusting feed formulations to match amino acid requirements reduces nitrogen excretion. Enzyme supplements and probiotics may also improve digestion and reduce ammonia in manure.

6.4 Housing Design
Well-insulated poultry houses with good drainage and properly installed nipple drinkers minimize litter moisture. Preventing condensation on walls and ceilings also helps keep humidity under control.

6.5 Advanced Methods
Technologies like air scrubbers, biofilters, or controlled ozone applications are being tested for large commercial units. Automated environmental control systems that integrate NH₃ and RH sensors with fans and heaters are becoming increasingly popular.

7. Economic Importance
Poor air quality silently eats into farm profits. Lower feed efficiency, reduced weight gain, carcass downgrades, increased mortality, and higher veterinary costs all add up to significant economic losses. Studies show that ammonia-related performance drops can cost large poultry complexes thousands of dollars weekly. Investing in better litter management, ventilation, and nutritional adjustments often proves cost-effective in the long run.

8. Evidence and Case Studies
Field surveys often reveal ammonia exceeding safe levels during winter when ventilation is minimized, leading to higher respiratory issues and welfare concerns. Controlled trials consistently show that birds exposed to even moderate ammonia (20–30 ppm) suffer from lower growth rates, poorer immune response, and more lesions compared to those raised under optimal conditions. Interventions such as litter acidifiers, improved diet formulations, and enhanced ventilation schedules have been shown to significantly reduce ammonia emissions and improve performance.

9. Recommendations for Farmers
– Check RH daily: maintain between 50–70%.
– Monitor ammonia regularly: aim for <20 ppm.
– Fix water leaks immediately to avoid wet litter.
– Adjust ventilation by season to balance temperature, RH, and air quality.
– Work with a nutritionist to optimize protein levels in diets.
– Use litter amendments wisely to reduce ammonia emissions.

10. Future Outlook
The integration of smart sensors and artificial intelligence into poultry housing systems may soon allow farmers to predict ammonia build-up and adjust ventilation automatically. Further research is needed to quantify the long-term welfare and production benefits of advanced technologies and to make them affordable for small- and medium-scale farmers.

11. Conclusion
Ammonia and humidity are closely linked environmental challenges in poultry houses. Both negatively affect bird health, welfare, and productivity when not controlled. Together, they magnify each other’s harmful effects, resulting in economic losses and compromised flock performance. Regular monitoring, proactive litter and ventilation management, balanced nutrition, and modern environmental control tools are essential for maintaining a healthy environment. Addressing these issues not only supports profitability but also improves animal welfare, ensuring sustainable poultry production.

In today’s poultry industry, two factors play a decisive role in ensuring profitable, sustainable, and disease-free production:

Water Treatment and Biosecurity.
Together, they safeguard flock health, enhance performance, and reduce dependence on antibiotics.

1. Water Treatment in Poultry
Water is often called the “forgotten nutrient,” yet it is the most critical element in poultry production. Birds consume twice as much water as feed, and any compromise in water quality directly impacts growth, egg production, and immunity.

Key Challenges in Water Quality
– Microbial contamination: Bacteria such as E. coli and Salmonella spread through untreated water.
– Biofilm formation: Organic residues in pipelines harbor pathogens.
– Chemical impurities: High TDS, hardness, iron, or nitrates affect digestion and performance.
– pH imbalance: Acidic or alkaline water reduces feed intake. Water Treatment Practices
– Filtration to remove physical impurities.
– Acidification to maintain pH (5.5–6.5) and inhibit bacterial growth.
– Chlorination / Hydrogen Peroxide / Ozone for disinfection.
– Regular waterline flushing to prevent biofilm buildup.
– Monitoring TDS, hardness, and microbial load routinely.

2. Biosecurity in Poultry
Biosecurity means preventing disease entry and spread on the farm. With rising concerns about Antimicrobial Resistance (AMR) and the push toward antibiotic-free production, biosecurity has become more important than ever.

Three Levels of Biosecurity
1. Conceptual Biosecurity – Farm location, distance from other poultry units, controlled entry points.
2. Structural Biosecurity – Physical barriers, fencing, bird-proof sheds, water sanitation system.
3. Operational Biosecurity – Day-to-day practices like disinfection, vaccination, and visitor control.

Practical Biosecurity Measures
– Restrict farm access (only authorized persons allowed).
– Provide footbaths, hand sanitizers, and farm clothing.
– Disinfect vehicles, crates, and equipment before entry.
– Implement rodent and wild bird control programs.
– Maintain strict mortality disposal methods (incineration/composting).
– Regular vaccination and health monitoring.
– Keep detailed farm records for traceability.

3. Water Treatment + Biosecurity = Sustainable Poultry
While water treatment ensures internal health and performance, biosecurity provides external protection from infections. Both are complementary and essential.
– Clean water reduces gut-related diseases like colibacillosis and diarrhoea.
– Biosecurity reduces the risk of respiratory and viral infections.
– Together, they help in antibiotic-free poultry production, improve FCR (Feed Conversion Ratio), enhance bird welfare, and boost farmer profitability.

Water Quality Monitoring & Water-Borne Diseases in Poultry

Diagram shows that, the source of water we need to check, Ph, TDS, COLOUR, BACTERIA & VIRAL LOAD. This water will go to overhead tank & from there it will distribute to different Poultry shed tanks & through pipe & nipple it will available for birds, here we need to monitor the quality of water.

Importance of Water Sanitation in Poultry Production
In modern poultry production, the use of feed additives such as water and feed acidifiers, toxin binders, probiotics, and antibiotic growth promoters (AGPs) is a common recommendation by poultry nutritionists. Farmers are also increasingly incorporating low-cost protein sources like Rice DDGS, Maize DDGS, and Meat Meal (sometimes adulterated with leather powder) to reduce feed costs.

However, ignoring water sanitation remains one of the most critical mistakes in poultry farming. Even with balanced feed formulation and additives, if the water provided to the birds is contaminated, it results in:
• Loose droppings due to microbial contamination.
• Poor nutrient absorption – birds fail to utilize protein, energy, minerals, and vitamins in the diet.
• Increased incidence of diseases such as E. coli infections and Salpingitis.
• Weakened immunity and consequently poor production performance.

In contrast, a farm with proper water sanitation shows remarkable differences. For example, in one of my ideally managed farms, the birds consistently showed dry droppings (“DRY BEAT”), a clear indicator of good gut health and proper nutrient absorption. This success was achieved through:
• Regular water sanitation practices (disinfection, acidification, and monitoring).
• Ensuring feed hygiene along with the use of safe, food-grade raw materials.
• Strict biosecurity and management protocols.

Safe Water Treatment – A Farmer’s Responsibility

Many farmers currently use different chemicals such as chlorine gas, bleaching powder, and sodium hypochlorite for water treatment. They are not safe for poultry or humans. These compounds often leave harmful residues, alter water taste, reduce consumption, and may even add toxic by-products into the water. According to WHO guidelines, only food and pharmaceutical grade salt should be used for drinking water treatment — both for humans and poultry. The safest and globally recommended option is NaDCC (Sodium Dichloroisocyanurate), which ensures:
• Broad spectrum disinfection with very effective bacterial control
• Safe for poultry & human consumption
• No significant change in taste or odour
• Eco-friendly & easy handling
• Stable and longer shelf life compared to other chlorine sources

Using sub-standard chemicals not only compromises poultry performance (loose droppings, poor nutrient absorption, higher
disease load, chlorine toxicity) but also risks human food safety through residues in meat and eggs.
Key Impact: Farmers must understand that safe water treatment is not about the cheapest chemical, but about using WHO- recommended, food & pharma grade NaDCC for long-term health, productivity, and profitability.

Note: Why NaDCC (Food & Pharma Grade) is Always Better.

Among all the available chlorine-base compounds for water sanitation, Food & Pharma grade Sodium Dichloroisocyanurate (NaDCC) is the safest and most effective choice.

• WHO Recommended – Approved for safe drinking water treatment globally.
• Broad Spectrum Effectiveness – Provides strong and stable disinfection (48 hours’ stability).
• Safe for Birds & Humans – No harmful residues, no significant change in taste or odor.
• Eco-Friendly – No toxic by-products or sludge formation.
• Long Shelf Life – Up to 3 years, with easy effervescent tablet formulation.
• Ease of Use – Simple handling, no heavy cylinders or high manpower required.
• Therefore, NaDCC (Food & Pharma Grade) is always better than chlorine gas, bleaching powder, sodium hypochlorite, or halozone for ensuring Zero-Bacteria Water in poultry Farms.

Conclusion
In poultry management, prevention is always better than cure. Poultry farming success is not just about what we feed the birds, but also about the quality of water they drink every single day. Feed can be fortified, sheds can be modernized, but without clean water and strict sanitation, the full genetic potential of the flock can never be realized. Water is the simplest yet most powerful tool to secure healthy birds, higher productivity, and long-term profitability. Water treatment and biosecurity are not costs but investments that return multiple benefits in productivity, profitability, and sustainability.

Dr.Partha P. Biswas
M.Sc.,Ph.D.,F.Z.S.,F.Z.S.I.
Former Asso. Professor & H.O.D.,
Dept. of Zoology, R.K.Mission V.C.College,
Kolkata ,W.Bengal.
Senior Consultant, Aqua-Vet inputs,
Fin-O-Wing Formulations, Kolkata-700084

The chicken industry is becoming more vulnerable to environmental shifts, particularly high temperatures. Open-sided poultry species are susceptible to heat stress, negatively impacting growth and productivity. Factors determining heat stress include temperature radiation, humidity, metabolic rate, age, and duration. Modern commercial broilers are more sensitive to heat stress, making understanding and controlling environmental conditions crucial for poultry production and health. High temperatures in birds reduce antioxidant capacity, requiring food handling and expensive cooling. Understanding and controlling environmental conditions is crucial for poultry production and health.

Thermoregulatory Device in Chicken
Unlike mammals, birds do not have sweat glands, but they have developed a number of behavioral adaptations to cope with heat, including increased breathing rate, panting and raised wings. Commercial poultry prioritize high production, making broilers more sensitive to environmental stresses, and affecting meat quality and immune problems. Under conditions of heat stress, metabolic heat increases, and the animal succumbs to hyperthermia. In summary, it can be concluded that high ambient temperature outside the thermoneutral region during the production phase has a bad effect on meat production, meat quality and causes serious immune problems in broilers.

Heat Shock Proteins of Poultry Birds During Heat Stress
Heat shock proteins (HSPs) are stress proteins found in all living organisms that are activated by high environmental temperatures to protect cells from stressors such as heat. The 70 kDa heat shock proteins (HSP70) are a family of proteins known for their potential role in thermotolerance and widely regarded as cellular thermometers. Over expression of HSP70 has been observed under oxidative stress, leading to mitochondrial reactive oxygen species scavenging and pulmonary endothelial protection against bacterial toxins. They keep cells in order by synthesizing other proteins, attract immune cells and participate in protein assembly and degradation. Higher HSP expression is associated with better heat tolerance and is produced by all living organisms in high temperature environments.

Effects of Heat Stress in Poultry Birds
Reduced voluntary feed intake which affects the functionality of the entire digestive system High environmental temperatures activate the hypothalamus–pituitary axis, brain-gut axis and elevate plasma corticosterone concentrations, affecting the digestive system’s functionality.

This leads to changes in motility, flux patterns, secretory activity, content viscosity and pH Generation of ROS (reactive oxygen species) and the efficacy of the antioxidant defense system deteriorate. Overproduction of ROS in mitochondria can damage proteins, lipids, and DNA Heat stress can impair the feeding process, nutrient absorption and utilization, although water intake increases rapidly Upregulation of adipokines secretion (leptin and adiponectin) and the expression of their receptors can negatively regulate feed intake and calorie consumption thus resulting in decreased metabolic heat production The decline in trypsin, chymotrypsin and amylase (intestinal secretion) due to reduced feed intake often results in impairment of digestive functionality, nutrient digestibility Hypoperfusion and an increase in blood flow to the skin surface occur as an adaptive response of the circulatory system to stabilize blood pressure and promote heat loss It is known that heat challenge has an immune-suppressive effect.

Use of Dietary Phytochemicals to Reduce Heat Stress
Experimental studies on poultry birds suggest phytochemical ingestion may reduce heat stress effects. These phytochemicals can directly or indirectly influence genes and metabolic pathways, with stress reduction linked to antioxidant qualities.

Fig.3: The chicken’s response to being overheated. Chickens raised in high temperatures produce more reactive oxygen species and show signs of immunological inflammation in addition to consuming less food.

Mitigating Heat Stress Using Epigallocatechin-3-Gallate (EGCG), A Secondary Metabolite in Green Tea

Green tea’s most prevalent catechin, EGCG, is thought to be its most bioactive ingredient and possesses potent antioxidant properties. The primary cause of heat stress-induced oxidative stress in poultry is damage to tissues and cells, which is mostly manifested in an increase in MDA (malondialdehyde) concentration in such tissues and cells. It has been demonstrated that adding the polyphenol EGCG to broilers housed in thermoneutral environments may increase their antioxidant capacity. Acutely heat-stressed broilers may have greater antioxidant capacity and less oxidative damage in their muscles because EGCG may activate the Nrf2 signaling pathway.

Reducing Heat Stress in Broiler Chickens With Additional Ginger (Zingiber Officinale) and Onion (Allium Cepa)

Onion and its derivatives including saponins, aglycones, quercetin, cepaenes, flavonoids, organosulfurs, and phenolic compounds showed various pharmacological properties and therapeutic effects.When broilers are heat stressed, the combination of onion and ginger supplements increases the nutrition of the groups more than no supplementation.

According to research results, growth performance, carcass quality, antioxidant levels and immune system response of broilers are improved when fed 10 g of ginger and and 2.5 g of onion during heat stress. Ginger contains substances with powerful antibacterial and antioxidant properties, including chagaol, ginger diol and ginger diol. Ginger (2%) added to broilers suffering from heat stress significantly improved blood biochemical parameters and growth indicators compared to the control group.

Seeds of Black Cumin (Nigella Sativa) improve Bird’s Ability to Live in Heat-stressed Conditions

Black cumin seeds have been shown to have pharmacological and antibacterial properties and also contain drug-like compounds. The volatile oil (0.4-0.45%) contains saturated fatty acids, which include: nigellone, which is the only component of the carbonyl fraction. oil, thymoquinone (TQ), thymohydroquinone (THQ), dithymoquinone, thymol, carvacrol, α and β-pinene, d-limonene, d-citronellol, carvacrol, t-anethole, 4-terpineol and longifolin etc. Thymoquinone improves hatchability, pos-thatching performance and antioxidant activity of thermally stressed broiler embryos. Black cumin extract has been shown in trials to reduce serum MDA levels and protect against oxidative stress.

Hot Red Pepper (HRP) Reduces Heat Exhaustion in Birds

Ascorbic acid, or vitamin C, is abundant in capsaicin, a terpenoid found in HRP that helps prevent heat exhaustion in birds. Carotenoids, which are rich in vitamins E, C, and provitamin A (beta carotene), are known to have powerful antioxidant qualities that help prevent the damaging effects of free radicals and, in certain situations, oxidative stress, which can lead to cell death in broilers. Furthermore, it has been found that adding capsaicin, an active ingredient in red pepper that is present in grill feed at a dose of 50 mg/kg, can lessen the harmful effects of heat stress.

Moringa (Moringa Oleifera)helps to Survive Birds Under Heat Stress

Moringa leaves contain high levels of total polyphenols (260mg/100g), b-carotene (34mg/100g), kaempferol (34mg/100g), quercetin (100mg/100g), as well as a total antioxidant capacity of 260mg/100g. Kaempferol and quercetin are the flavonoids present in moringa leaves and possess strong antioxidants. It has been found that 0.3% incorporation of M. oleifera leaf meal improves the performance and physiological parameters of broilers and also helped the birds survive under heat stress.

THYME (THYMUS VULGAIS) Protects Chicks Against Heat Stress

The two most important bioactive compounds in this plant are carvacrol and thymol, which may be the primary source of thyme’s pharmacological actions. Thus research has identified linalool, thymol, carvacrol, gamma-terpineol, and geraniol as the primary components of thyme. Dietary thyme essential oil (150–200 mg/kg) is more effective at shielding chicks from the harmful effects of heat stress while also enhancing immunological function and development performance. One material that may be able to improve growth in broilers located in hot climates is thyme oil.

Coriander (Coriandrum Sativum) Seed in Ameliorating the Impact of Thermal Challenges

According to research, broilers under heat stress that are fed 2% coriander seed have higher feed intake, weight gain, reduced panting, and higher levels of corticosterone. The broilers’ poor intestinal absorptive capacity and shape may be connected to the rise in corticosterone levels during stress. Furthermore, according to a different study, adding 2% coriander to the diet helps broiler birds by lessening the effects of heat shock. The supplement, according to the author, benefitted broilers that were experiencing heat stress and enhanced their blood parameters, immunity, and overall performance.

Cinnamon (Cinnamomum Zeylanicum) Powder as Antioxidant in Thermally Challenged Birds

The common herbal plant, cinnamon contains different active phenolic compounds, which include flavones, catechin, isoflavones, flavonoids and other phenolics. The main bioactive constituent of cinnamon is cinnamaldehyde. The phenolic components function as antioxidants and can effectively scavenge ROS. Cinnamon supplements help in homeostasis due to the reduced pH caused by heat stress. It has also been reported that an increase in the activity of CAT, total antioxidant capacity and SOD and a decrease in the MDA when birds were placed in a thermally challenged environment during their finishing phase.

Turmeric (Curcuma Longa) for Heat-stressed Broilers

The yellowish pigments of turmeric, namely demethoxycurcumin, curcumin, and bisdemethoxycurcumin, are commonly referred to as curcumoids. Curcuminoids are an antioxidative compound found in turmeric. Researchers have shown the effects of turmeric powder supplement at 0.3 and 0.6 g/kg when administered to birds under heat stress. The superoxide radicals are neutralized, and there is an increase in the activity of SOD and CAT (ROS-removing enzymes or antioxidant enzymes ) and a decrease in MDA in broilers. The increased level in MDA indicates oxidative damage in liver of heat stressed broilers.

Conclusion
Heat stress can hurt poultry birds by making them grow slower, weakening their immune system, causing intestinal inflammation, and causing other health problems. It can also trigger oxidative process. But using natural substances called phytogenic compounds can help chickens who are raised in hot conditions.But more research is needed to understand the molecular changes made by medicinal herbs and the interactions between their active components, gut microbiota, and gut barriers. By using these approaches, we can improve chicken welfare and make poultry production more sustainable and efficient.