Hen nutrition must address a number of different goals, including maximizing egg production, maintaining egg quality, extending the laying cycle and ensuring hen health and welfare. This chapter focuses on the role of nutrition in optimizing energy intake, egg size and egg weight. It reviews the different nutritional requirements hens have in their pre-laying and laying phases; discusses how feed consumption can be controlled; and then reviews the effects of energy concentration, dietary lipids, dietary proteins and amino acids on egg weight. It also offers a discussion of how the inclusion of cereals and alternative protein sources in the diet can affect egg characteristics.