Heat Stress in Poultry: What the THI Index Means for African Farmers

Poultry farming is a cornerstone of food security and livelihoods across Africa. Yet, one of the biggest seasonal challenges farmers face is heat stress, which can reduce productivity, weaken immunity, and increase mortality rates.

Understanding the THI Index

The Temperature‑Humidity Index (THI) combines ambient temperature and humidity to measure heat stress risk. When THI values rise above safe thresholds, birds struggle to regulate body temperature, leading to reduced feed intake, slower growth, and higher susceptibility to disease.

The African Context

Africa’s climates vary widely:

• Dry regions (Sahel, East Africa) experience extreme daytime heat with low humidity.
• Humid zones (West Africa, coastal areas) combine high temperatures with moisture, pushing THI values even higher.
• Southern Africa faces seasonal heat waves that stress both broilers and layers.

Farmers across these regions often observe:

• Panting and wing‑spreading behavior
• Decline in egg production
• Increased water consumption
• Greater vulnerability to respiratory and metabolic disorders

Practical Solutions for African Farmers

Monitoring THI daily allows proactive interventions:

• Provide shade and natural ventilation in open houses
• Use cooling systems such as foggers, sprinklers, or fans
• Adjust feeding schedules to cooler hours (early morning, evening)
• Ensure constant access to clean water
• Explore climate‑smart poultry housing designs

Why It Matters

Heat stress doesn’t just affect bird welfare — it impacts profitability and food security. Early detection and intervention can reduce losses, improve productivity, and strengthen resilience against Africa’s increasingly unpredictable climate.