A hen requires about 24 to 26 hours to produce and egg. Thirty minutes later, she starts all over again. The reproductive system of the hen consists of the ovary, the organ where the yolk develops, and the oviduct where the egg is completed. The ovary is attached to the back about halfway between the neck and the tail. The oviduct, a tubelike organ approximately 26 inches long, is loosely attached to the backbone between the ovary and the tail.
Most female animals have two functioning ovaries, but the hen uses only one, the left.
The right ovary and oviduct remain dormant. Ovary A female chick is born with a fully formed ovary containing several thousand tiny ova, or future yolks. Each yolk is enclosed in its own sac or follicle. The follicle contains a highly developed system of blood vessels which carry nourishment to the developing yolk. At ovulation, the follicle ruptures to release the yolk into the oviduct.