Concerning the reduction of nitrogen inputs into Swiss agriculture, organic poultry farming is challenged. For animal welfare and naturalness, the use of dual-purpose chickens increased, which are often less efficient. It leads to the consideration of feeding extensive genetics with more extensive feed. As with the free range, this implies roughage, which increases the crude fibre content in the diet. Overall, there is a lack of data to evaluate and improve crude fibre intake and its influence on nutrient efficiency (especially protein efficiency) in poultry under organic conditions. Controlled feeding trials with broilers and layers will be conducted to determine voluntary roughage intake and the resulting nutrient efficiency, comparing hybrid breeds and dual-purpose chickens. Performance and product quality parameters will also be collected.
