Heat stress is a growing welfare challenge in intensive poultry production as climate change increases frequency of high temperature events. Broilers and laying hens are particularly vulnerable.
Heat-stressed poultry experience thermal discomfort, respiratory distress, and cardiovascular strain. Broilers with high breast muscle mass have reduced thoracic cavity volume and particular difficulty breathing in high temperatures. Panting and wing spreading are behavioural thermoregulation attempts that indicate significant thermal stress. Production systems with inadequate ventilation or emergency cooling can experience catastrophic mortality in heat wave events. Climate change makes heat stress adaptation in poultry housing an urgent welfare and business risk issue.