Healthy birds start with the right environment

Cold weather brings unique challenges for poultry producers. While broilers are bred for rapid growth and efficient feed conversion, they are particularly susceptible to cold stress, especially during the brooding period. Young chicks have a limited ability to regulate their body temperature and rely heavily on their environment to remain comfortable.

Cold stress occurs when temperatures fall below a bird’s thermoneutral zone. At this point, birds divert energy away from growth and production to maintain their body temperature. The result is poorer performance, higher production costs, and reduced profitability.

The impact of cold stress on broilers

When birds become cold, they consume more feed purely to produce body heat. While feed intake often increases, much of that energy is used for maintenance rather than growth.

Producers may notice:

• Increased feed consumption.
• Lower water intake.
• Reduced growth rates.
• Poorer feed conversion ratios (FCR).
• Uneven flock performance.
• Increased disease susceptibility.

Cold stress also affects gut health and immunity. Exposure to low temperatures increases the production of stress hormones such as corticosterone, which suppresses immune function and makes birds more vulnerable to disease challenges.

Cold stress can also increase the risk of ascites syndrome, sometimes referred to as pulmonary hypertension syndrome – a condition in which fluid accumulates in the abdominal cavity of the bird. It develops when the heart and lungs are unable to meet the body’s oxygen demands, causing increased pressure in the pulmonary circulation and placing strain on the heart. Fast-growing broilers, and particularly those produced at higher altitudes, are especially susceptible because of their high metabolic and oxygen requirements. As height above sea level increases, atmospheric oxygen availability decreases. Birds must therefore work harder to supply sufficient oxygen to their rapidly growing tissues. Cold conditions add to this challenge because birds increase their metabolic rate to generate body heat, further increasing their oxygen requirement. This combination can place additional pressure on the heart and lungs, contributing to pulmonary hypertension and, in susceptible birds, the accumulation of fluid in the abdominal cavity associated with ascites. Maintaining appropriate house temperatures, good ventilation and air quality, particularly at higher altitudes, is therefore an important part of reducing ascites risk during cold weather.

Watch your birds

Bird behaviour provides one of the quickest indicators of environmental conditions. Comfortable chicks will be evenly spread throughout the house, actively eating, drinking and resting.

Severely cold-stressed chicks often:

• Huddle beneath heaters.
• Become less active.
• Vocalise more frequently.
• Eat and drink less.
• Show uneven distribution.

Daily observation remains one of the most valuable management tools available.

Don’t overlook ventilation

One of the biggest mistakes is reducing ventilation to conserve heat. While this may keep houses warmer, it allows moisture and ammonia to build up.

Ammonia concentrations above 20 ppm can damage the respiratory tract, reduce welfare, and increase the risk of respiratory disease.

Maintaining adequate minimum ventilation helps remove moisture, carbon dioxide and ammonia while maintaining litter quality.

Practical cold weather management tips

To minimise cold stress:

• Monitor brooding temperatures carefully.
• Conduct crop checks within the first 48 hours.
• Ensure continuous access to quality feed and clean water.
• Maintain dry litter.
• Inspect heaters and ventilation equipment regularly.
• Observe bird behaviour every day using sight, sound, touch and smell.

A strong start leads to better performance

Small adjustments to temperature, ventilation and daily management help protect flock health, improve feed efficiency and maximise performance throughout the production cycle.

Technical input by Kyle Westergaard, National Poultry Technical Manager, EPOL.​