Organic broilers grow slower than conventional birds and so producers face the challenge of feeding quality feed components at lower concentrations. Feed needs to fulfil the amino acid and energy requirements of broilers for efficient growth and development, but growth is slower.
Choice feeding, access to range and forages can increase the utilisation of protein and energy, which will increase feed efficiency. The requirements for birds to use the range area is part of the solution.
Organic standards require organic broilers to be free range and have access to open-air spaces as soon as possible (figure 1) but at a minimum of one-third of their life. The minimum slaughter age for broilers is 81 days.
• Feed components should contain high-quality proteins, e.g., legumes, aquatic feed sources and by-products from food manufacturing and industrial processes.
• Organic standards prevent the use of synthetic amino acids, so there is a need to ensure amino acid availability (especially methionine and lysine).
• A phase feeding strategy should be used to account for the differences in the dietary needs of broilers dur-ing different growth stages.
• Account for feed consumed in outdoor areas (i.e., roughages) when calculating nutritional requirements and formulating feed rations.
• Formulate diets on a digestible amino acid basis rather than on a total amino acid or crude protein level.
• Choose appropriate breeds that are able to perform with the given resources, particularly slower-growing breeds.
Slower-growing breeds will need less energy-dense rations and are also more inclined to seek food in the range.
Choice feeding, where birds select separate foods, rather than manufactured compound feed, has been found to increase Feed conversion efficiency (FCE) when birds have access to range.
Limiting protein intake for organic broilers in the finishing stages can be an acceptable feeding strategy if the broilers have access to vegetation with a high nutritional value. Reducing protein levels for slow-growing breeds to 15% resulted in a lower FCE but a lower cost of production.
Key to this is range management and alternative forages, such as baled haylages, which will be needed during winter or drought periods. High protein sources such as lucerne and clovers can also supply some of the required protein. Account can also be taken of insects and invertebrates eaten on the range, which can supply some of the protein and amino acids required.