As our planet’s climate continues to warm, the global poultry industry, specifically broiler farming, stands at the forefront of the heat-driven battle. The intricate relationship between hot climates and broiler farming is one that poultry farmers in the Caribbean should carefully consider, both to understand how it impacts their chickens as well as to help develop innovative strategies to combat the extreme effects of excess heat.

The Farming Landscape

Broiler farming, the practice of raising chickens for meat production, has become a cornerstone of the global food industry. These chickens, bred for rapid growth and high meat yield, fuel the demand for poultry products worldwide. However, as temperatures rise due to climate change, the very conditions that support this industry become its greatest adversary.

At the heart of the broiler chicken’s journey from egg to plate lies the concept of metabolism. Metabolism encompasses the intricate web of biochemical processes within the chicken’s body that convert feed nutrients into energy for growth, movement, and maintaining vital functions. The energy generated during metabolism is essential for various physiological processes, including muscle activity, organ function, and heat production.

Thermogenesis: Natural Heat Production

Thermogenesis, the process by which living organisms produce heat, plays a pivotal role in a broiler chicken’s life. In a normal environment, the heat generated during metabolism aids the bird in various ways:

1. Maintaining Body Temperature: Broiler chickens are warm-blooded creatures, meaning they maintain a constant internal body temperature irrespective of external conditions. The heat generated through metabolism contributes to sustaining this optimal body temperature. In cooler environments, it’s a protective mechanism against cold stress.
2. Digestion and Nutrient Utilization: The heat produced during metabolism enhances digestion and nutrient utilization. The energy generated supports the breakdown of complex nutrients into simpler forms, enabling better absorption and utilization of nutrients from the feed.

Broilers generate a surprising amount of heat through their metabolic processes – on average, approximately 10-15 BTUs (British Thermal Units) of heat per hour. To put this into perspective, a 100-watt incandescent light bulb generates around 341 BTUs of heat per hour. 25 full-sized broilers standing together eating feed will produce as much heat energy as a 100-watt bulb! A flock of 1000 broilers metabolizing feed is equivalent to the energy output of forty (40) 100-watt light bulbs. When you look at it from this perspective, that’s a lot of heat being added to the air inside the poultry house.

The Impact of Hot Climates

Now, imagine subjecting broiler chickens to hot climates like those in Barbados and the wider Caribbean. In hot weather, when the ambient temperature rises, chickens struggle to regulate their body temperature effectively, leading to overheating. This can result in reduced feed intake, decreased growth rates, and even heat-related health issues. Proper ventilation, shade, and access to cool, fresh water are essential for helping broiler chickens cope with high temperatures and avoid heat stress.

• Heat Stress: As temperatures rise, the chickens struggle to maintain their internal body temperature. Their metabolism is pushed into overdrive as they attempt to cool down. This excessive energy expenditure diverts resources from growth and productivity, resulting in reduced feed intake, slower growth rates, and compromised immune systems.
• Increased Water Demand: Just like humans, chickens use water to regulate body temperature. In hot climates, the birds drink more water to cope with the heat. This increased water demand can strain water resources on the farm and escalate operational costs, as well as add too much moisture to the litter which can spiral into health issues when microbes start to flourish.
• Ventilation and Air Quality: Proper ventilation becomes paramount in hot climates to ensure the flow of fresh air through the broiler houses. Poor ventilation, coupled with high outside air temperatures, can lead to very exaggerated temperatures around the body of the broiler, leading in turn to overheating. Good ventilation also helps remove moisture from the litter.
• Disease Susceptibility: High temperatures and humidity create a favourable environment for pathogens to flourish. Broiler chickens experiencing heat stress become more susceptible to diseases, leading to increased mortality rates and additional economic losses for farmers.

What temperature is considered “too hot”?

Broiler chickens are sensitive to temperature extremes, and a temperature that is considered too hot for older birds typically falls within the range of 85 to 90 degrees Fahrenheit (29-32 degrees Celsius). Beyond this point, heat stress becomes a significant concern for these birds. Unlike humans who sweat to cool down, chickens lack sweat glands. Instead, they primarily rely on evaporative cooling mechanisms, such as panting and spreading their wings, to dissipate excess body heat.

When the difference between air temperature and body temperature gets smaller, the chicken loses heat less quickly. The combination of air that is already hot in the Caribbean, and the large amount of energy being produced when a chicken eats normally, means that if air is not moving through your pen the broiler will have a hard time shedding its body heat. Which leads to less eating, less growth, and less profitable broiler production.

What strategies can we use to combat the impact of heat on broilers?

In the Caribbean, summer months can bring extreme high daytime temperatures – sometimes the air being forced through a broiler house is already hotter than the broiler can tolerate. Ventilation might remove overheated air inside the house, but it is replacing it with air that is still too hot for the broilers. What can farmers do about this?

1. Cooling the drinking water: Most small farmers in the Caribbean have access to inexpensive plastic 55-gallon drums that make good reservoirs for gravity feeding bell and nipple drinkers. These drums are often dark colored and installed in direct sunlight, and are also often supplied by water pipes that run on the surface of the ground or roadway. These all contribute to heat absorption from the sun’s rays, heating up the drinking water being fed to the broilers. Hot water is not palatable to humans, nor to chickens, so it will not be consumed readily. Chickens that don’t drink, wont eat!
   • Cover the drum or reservoir to avoid heating by the sun
   • Cover the pipes feeding the reservoir to avoid heating by the sun
   • In extreme cases, add ice to the drinking water mid-morning or midday to give a period of cooler water, which leads to more drinking and more eating.
2. Cooling the broiler house: Evaporative cooling systems, like those used in tunnel houses, cool the incoming air down to a more comfortable temperature. Conventional, open sided houses can use misting systems, and standing fans to circulate the air around the birds to encourage heat loss.

Wet your broiler house roof with a hose on the hottest days to remove some of the heat stored in the galvanise sheets. Planting large shade trees near to your broiler house can also reduce direct heating from the sun. Insulation  applied under the roof (spray foam, fiberglass matting, polystyrene sheets) will reduce the heat that can be radiated from the roof material down into the broiler spaces.

3. Nutritional Adaptations: Adjusting feed formulations to include additives such as electrolytes and antioxidants helps broilers combat the effects of heat stress. These additives aid in maintaining hydration and supporting the birds’ immune systems during challenging conditions. Electrolytes such as Kepro® Stress Aid can be easily mixed into drinking water.

Conclusion: Navigating the Heat Wave

Successful broiler farming in the Caribbean requires careful attention to the added impact of heat generated by broilers when they consume and metabolize feed. Most farmers can feel when “it is hot” – especially in summer months, July 2023 having the highest global monthly average temperature ever recorded – but they must also recognize that their broilers are packed together in a dense population, they generate far more body heat than people do (per kg of body weight) and they will drink more water and eat less feed as a way to combat the heat.

Don’t guess at the broiler house temperature – measure throughout the day with a thermometer and take cooling steps if they are needed. We have recently visited customers who normally get great broiler results, but at 3 and 4 weeks their birds are experiencing 36 degree litter temperatures. Even with fans circulating air, these temperatures will damage your broiler’s ability to grow properly.

Keep your hi-tech broilers cool and they will reward you with good growth rates and low mortality!