Ovulation: Hens and ducks are capable of producing and releasing one egg at a time. The process begins with ovulation, which occurs within the hen or duck's reproductive tract. During ovulation, a mature egg yolk is released from one of the ovaries.
Traveling the Oviduct: The egg yolk then begins its journey through the oviduct, which is a muscular tube leading from the ovary to the cloaca (the common opening for the digestive, excretory, and reproductive systems).
Adding Albumen: As the egg yolk moves through the oviduct, it gets covered with layers of albumen (the egg white). The oviduct secretes this thick, protective fluid, which helps cushion and protect the developing embryo.
Forming the Shell: The egg then enters the shell gland, also called the uterus. Here, multiple layers of calcium carbonate are deposited onto the egg, creating the hard and calcified eggshell that we are familiar with.
Colors: The shell may acquire different colors and patterns depending on the species and genetics of the hen or duck.
Finishing Touches: Additional structures are formed as the egg moves through the oviduct, such as the chalazae (the small white strands that hold the yolk in place) and the cuticle (a protective coating that helps prevent bacterial contamination).
Laying the Egg: Finally, the fully formed egg reaches the cloaca and is ready to be laid. When the hen or duck decides it is time, the muscular contractions of the oviduct and the cloaca push the egg out of the body.
It is important to note that egg formation, which involves the development and release of the yolk, as well as the accumulation of albumen and the shell, is a physiological process that occurs naturally within the reproductive systems of these birds.