Since feeding was usually ad libitum, the principal way of attempting to control nutrient intake was to vary the composition of the food. Ideally, diet composition should be varied every day, rather than in a few step changes, because of the continuously changing needs of the birds. This facility was available in the FLOCKMAN system, which automatically measured the feed intake and bird weight, and provided nutrition control by blending two feeds (Filmer, 2001) from separate silos.One silo contained a series of different compound feeds, for example starter, grower and finisher rations, containing different concentrations of amino acids, fats and other nutrients, appropriate for birds of different ages. The othersilo contained whole wheat, to provide a low cost, low protein energy source that could be mixed with the compound to fine-tune the nutrient supply. The inclusion of even a small proportion of whole wheat in the diet has been shown to have beneficial effects (Filmer, 2002). The management system mixed the two feeds in the required proportions by weight according to the specifications given by the operator. Two instrumented bird weighers (Turner et al., 1984), a water meterand a feed weigherwere installed in each house.The system therefore collected daily information on bird growth and nutrient supply.