In the production cycle of the commercial
layer, the hen will begin to lay small eggs
and in a matter of few weeks will go to
medium size and then to the desired large
size egg. Although egg size can be
manipulated using fat levels, protein and
enzymes, some other factors such as age
and body weight of the hen, yolk weight and
nutrient intake can influencing egg size.
Asuquo and Okon (1993) studied the effects
of age in lay and egg size on fertility and
hatchability of eggs.