To counteract declining quantity and poor quality of paddock feed over summer/autumn, farmers in Western Australia must decide how much of which supplement to provide to grazing sheep to optimise the use of supplements. The solution is complicated by the interaction of biological and economic factors and the intertemporal nature of the problem. A dynamic programming approach was used to determine optimal feeding strategies for different starting conditions. Lupin seed was preferred to oats for weaners when paddock feed was abundant, while oats was preferred for weaners and adults when paddock feed was scarce. The optimal feeding rate usually starts low and then gradually increases to higher rates as the autumn break approaches.