Lash eggs result from an infection that causes inflammation of a hen’s oviduct. That inflammation is referred to as Salpingitis. The hen’s immune system reacts to the inflammation by trying to wall-off the infection with a waxy, cheese-like pus. This pus mass may or may not contain yolk, albumen, (egg white) eggshell, egg membrane, blood or pieces of tissue from the oviduct wall, but it is primarily a yellowish, cheesy, pus ball.