Mortality rates in laying hen flocks are a key welfare indicator, with excess mortality from disease, injury, and management failures representing a significant and measurable welfare problem in egg production.
Laying hen mortality rates tell part of the welfare story of egg production. High mortality indicates a welfare crisis — birds are dying from conditions that cause suffering before death. But mortality is a lag indicator: the suffering that precedes death — from keel bone fractures causing pain with every wing flap, from respiratory disease causing labored breathing, from feather pecking injuries — is not captured by mortality data alone. A flock with low mortality may still have widespread keel bone fractures affecting welfare without threatening survival. Comprehensive welfare monitoring that captures both mortality and disease/injury prevalence is needed to fully characterize flock welfare.