Abstract: Egg weight, shape and shell colour are external characteristics that influence egg grading, packaging, price, consumer preference and hatchability. It is therefore important to understand the factors that influence them. Within a species, egg size may differ with younger birds of a species laying smaller eggs than older birds. Egg weight varies according to the oviposition time. Age of the hen is also important in determining egg weight which increases with increasing age. Higher bodyweights are generally associated with bigger eggs. Nutrition can partially control late egg size and the most important nutrients for control of egg size are linoleic acid, protein and specific amino acids. Lighting programmes influence egg size by accelerating or delaying the age at which hens start to lay eggs. The younger a hen is when she starts egg production, the smaller her eggs will be during her 1st year of life. The greatest consumer demand is for large and extra large eggs. Egg size affects hatchability and the hatchability for small eggs is lower compared to that of medium and large eggs.