Non-starch polysaccharides (NSPs) have antinutritional effects on boiler chickens; insoluble NSP act as nutrient diluents and physical barriers to enzymes and soluble NSP increase digesta viscosity, thereby reducing efficient digestion and absorption of starch, protein and lipids. To overcome these antinutritional effects, NSP degrading enzymes (NSPases) are readily supplemented into broiler diets. This investment explores the use of customised NSPase to target specific NSPs in boiler chicken diets as well as the potential influence of chicken age on response to NSPases and NSPs in the diet.