collection of water, proteins, and some carbohydrates, lipids, and minerals that surround the egg and yolk to nourish the growing embryo, provides cushioning as the egg is moved around in the nest cup, helps hold the internal temperature of the egg when parents are not tightly incubating; accumulates in layers during the egg’s journey through the oviduct: in the infundibulum a thin layer of viscous (dense) materials, including the chalazae (stringy strands extending out from the yolk and connecting to the shell, suspending the developing embryo and the yolk in the albumen), in the magum a thin watery layer and a thick viscous later (the largest proportion of albumen), in the isthmus another thin watery layer; more fluid added in the uterus, referred to as “plumping”; shrinks as water and proteins are absorbed by the embryo and water is evaporated through the shell