Summary of paper presented at the Australian Poultry Science Symposium in Sydney, Feb 2013
Birds attempt to consume sufficient of a given food to enable them to meet their nutrient requirements for maintenance, growth and/or egg production, but may fail to do so when constrained by a bulky feed or the inability to lose sufficient heat to the environment. Under constrained conditions maintenance requirements are the highest priority, with potential growth or egg production being reduced in proportion to the constrained intake. Thus, food intake will be governed by the potential performance of the bird, the limiting nutrient in the feed, and any constraints that may reduce the desired intake. The accurate prediction of food intake by a given animal on a given food when housed in a given environment makes it possible to define the optimum economic levels of energy and essential nutrients in feeds for broilers and laying hens thereby improving the method of choosing nutrient specifications to be used in least cost feed formulation. Such systems thinking and modelling, when applied to the problem of feed formulation, leads to a more rational approach in which nutritional decisions are made entirely in terms of the objectives of the business. This advanced approach cannot be achieved without being able to predict voluntary food intake accurately under the conditions encountered in commercial poultry operations.