The selection of chicken breeds for commercial egg and meat production has profound welfare consequences, with slower-growing and dual-purpose breeds offering significantly better welfare outcomes.
Breed selection is among the most fundamental welfare determinants in commercial poultry production because it establishes the physiological baseline within which all management operates. The most intensively selected commercial broiler breeds have been developed to grow at rates that cause widespread musculoskeletal, cardiovascular, and metabolic disease - health problems that are not management failures but are the direct consequence of the genetics. Slower-growing breeds that grow at 25-40% the rate of commercial types show dramatically lower rates of lameness, ascites (fluid accumulation from cardiovascular strain), and mortality - welfare improvements that cannot be replicated by improving management of fast-growing breeds. The Label Rouge system in France demonstrates that slower-growing breeds can be commercially viable in appropriate market segments that value welfare and quality. For laying hens, the selection for maximum annual egg production has trade-offs in bone mineral density and keel bone integrity - hens producing 300+ eggs annually face significant calcium depletion that contributes to keel bone fractures. Dual-purpose breeds that provide both eggs and usable meat from male chicks address not only laying hen welfare but also the welfare harm of male chick culling that characterises specialised laying breed production.