Inclusion of distillers' dried grains with solubles (DDGS) has been shown to reduce the metabolisable energy (ME) of poultry diets. It is not known what effect this ingredient has on heat production and therefore dietary net energy (NE), especially when included at high levels. In terms of NE, the effectiveness of enzyme addition for such diets is also unknown. The present study was designed to evaluate the impact of DDGS, as a fibrous ingredient, on the energy utilisation of broiler chickens using the indirect calorimetric method.