Today’s commercial poultry production is about making decisions and implementing them, the main objective being to maximize profit for the enterprise. Alternative courses of action should be thought of and the consequences of these actions need to be predicted. Animal nutritionists face various problems when formulating feeds for poultry. Advances in simulation modelling have made it possible to look into all aspects of production when formulating feeds for animals. This chapter deals with these issues and looks at the use of simulation models to optimize poultry production. The goal of nutritionists and modellers is to predict the responses of the poultry to nutrients. This chapter looks into this issue. The chapter also describes the methods used to predict the potential laying performance of hens and the environmental factors that affect the desired feed intake. Finally, this chapter also explains how models can be used to optimize feeding programmes.