Rising global temperatures are increasing the frequency and severity of heat stress in livestock, with significant welfare implications for animals whose physiological cooling capacity is limited.
Heat stress causes genuine suffering in livestock. Affected animals display open-mouth breathing, reduced activity, elevated cortisol, and immune suppression. In extreme cases, heat kills thousands of animals rapidly — mass mortalities from heat waves in broiler and laying hen sheds have increased in frequency. Climate adaptation in animal agriculture requires welfare-informed redesign of housing, breeds, and management rather than purely productive responses.