A litter consisting of a period of continuous production with out break. Each litter composed of clutches , clutch is continuous production successive days with eggs on either end of the litter being smaller than those in the middle of litter. With the amount of ration and water fed the hens having great effect on egg weight. Also the 2nd egg of a 2 egg clutch is smaller than the first egg. The parts of the egg, yolk, albumen, shell weight show seasonal functions.
Shell weight varies more than the other two.
Whereas the albumen weight varies more than the yolk weight. The different degrees of albumen secreted by the oviduct is what determines the amount of yolk. Thus the chickens body has physiological processes determining either of these. The hens body has a normal make up , you get regular sized eggs. Whereas if the hens body has abnormalities, she lays dwarf eggs.