Poultry Metabolic Disease and Welfare

Metabolic diseases in laying hens and broilers, driven by genetic selection for production traits, cause significant welfare impairment that is intrinsic to high-performance breeds.

Key Facts

Fatty liver haemorrhagic syndrome affects laying hens in cage-free systems at high rates due to lipid metabolism disruption.
Sudden death syndrome in broilers causes rapid cardiac arrest in the fastest-growing birds with apparently good health.
Ascites in broilers — fluid accumulation from cardiac strain — affects 1-4% of commercial birds in some production systems.
These metabolic conditions are directly linked to genetic selection for rapid growth and high egg production rates.
Slower-growing and lower-production breeds show dramatically lower rates of metabolic disease.

Welfare Considerations

Metabolic diseases in commercial poultry are not management failures — they are predictable consequences of genetic selection that has pushed physiological limits to and beyond their sustainable boundary. Sudden cardiac death, liver haemorrhage, and ascites affect birds that appear healthy until the point of acute crisis, representing welfare failures that cannot be addressed by improved husbandry alone. Genetic breed selection is the root cause and must be addressed to achieve meaningful welfare improvement.

What You Can Do

Support industry adoption of slower-growing and lower-intensity laying breeds that reduce metabolic disease rates.
Choose poultry and egg products from breeds certified under welfare standards requiring metabolic health indicators.
Support regulatory requirements for breed welfare criteria in poultry assurance schemes.
Reduce poultry and egg consumption and shift to plant-based alternatives to reduce demand from high-production systems.