Broiler diets are routinely supplemented with approximately 50 g/kg lipid. The lipid supplement used in the UK has been a blend of tallow and vegetable oil, however, there is considerable interest in the use of alternative fat sources. The fatty acid composition of supplemental lipids, in particular the degree of unsaturation of fatty acids can (1) effect lipid digestibility and may be reflected in differences in growth performance and (2) markedly influence tissue fatty acid profiles which may increase the requirement dietary antioxidant supply and affect meat storage characteristics.