Poultry are highly susceptible to heat stress due to their limited ability to thermoregulate, and climate change is making this a growing welfare problem in UK and European farms.
Poultry experiencing heat stress show panting, wing-dropping, reduced movement, and in severe cases collapse and death. Birds in intensive sheds with high stocking densities are most vulnerable due to metabolic heat generation from neighbours. Power failures affecting ventilation systems during heat waves have caused mass mortality events. The welfare cost of heat stress is increasing with climate change and will require proactive adaptation in farm design and management.