ABSTRACT
The organic production system is an important rearing system that is compatible with sustainable animal production (Castellini et al., 2006). The US Congress passed the Organic Food Production Act in 1990 (Oberholtzer et al., 2006); organic poultry production system standards were subsequently established within the National Organic Program (NOP) by the United States Department of Agriculture (USDA) in 2002. The USDA determined the goals of organic poultry production and these were aligned with ‘cultural, biological and mechanical practices that support the cycling of on-farm resources, promote ecological balance, and conserve biodiversity’ (https://www.ams. usda.gov/sites/default/files/media/NOP-2015StrategicPlan.pdf). These standards were similar to those established by the International Federation of Organic Agriculture Movement (IFOAM) and were overseen by the joint Food and Agricultural Organization/ World Health Organization (FAO/WHO), and these standards were established in 1963 (www.ams.usda.gov/nop). The guidelines were established to promote a sustainable method of rearing poultry in an environment that allows natural behaviour to be expressed and eliminates pesticides, herbicides and other chemicals from feed, growing environment and carcass processing. While the definition concentrates on the physical factors of rearing, greater focus on the humane aspects such as outside access, sunlight, bird density and enrichment have dramatically changed the housing systems for meat and egg production.
