Laying Hen Mortality: Causes and Prevention

Mortality in laying hen flocks reflects welfare status — high death rates from disease, cannibalism, and smothering indicate systemic management problems.

Key Facts

EU regulations require keepers to act when mortality exceeds 0.5% per week or 1% per month
Keel bone fractures, while not directly causing death, predispose hens to reduced mobility and secondary welfare problems
Smothering events — where hens pile on top of each other — occur particularly in large cage-free flocks during disturbances
Marek's disease, Newcastle disease, and infectious bronchitis are leading causes of infectious mortality
Higher-welfare systems with good management consistently achieve lower mortality rates than conventional systems

Welfare Considerations

Mortality rate in laying hen flocks is a sensitive indicator of welfare status. Deaths from cannibalism reflect enrichment failure; smothering deaths reflect poor flock management and panic response; infectious disease deaths reflect biosecurity and vaccination failures. The European regulatory threshold of 1% monthly mortality is a minimum intervention trigger, not a welfare target — well-managed free-range flocks can achieve under 0.5% monthly mortality. Systematic mortality recording, investigation of cause, and management response create a continuous improvement cycle that benefits welfare.

What You Can Do

Support certification standards that require mortality investigation and recording
Advocate for welfare-based mortality benchmarks in laying hen assurance schemes
Choose eggs from producers with documented low mortality rates
Support research into the causes of laying hen mortality in different housing systems
Engage with mortality as a welfare outcome measure in your advocacy and communications