A knowledge of the anatomy and physiology of an animal is essential for understanding, and correcting, any problems that may arise. For example, Knowledge of the digestive system assists in understanding the nutritive requirements of chickens. In addition, knowing what’s ‘normal’ can also help you recognize and take action when the digestive system goes awry. Similarly, knowledge of the female reproductive system is important for understanding any problems that may arise with regards to egg production, fertility, and hatchability.
UNIVERSITY OF KENTUCKY FACTSHEETS
Chickens are omnivores, meaning they eat both plants and animals. In the wild chickens often scratch in the soil to search for seeds and insects. They also eat larger animals such as lizards and young mice.
Unlike cows, chickens do not have a rumen so are not able to digest the cellulose of forage. This is important when pasturing chickens.
Feed passage in broilers - A complex problem (University of Florida)
Poultry eggs are part of a unique reproductive system. The egg serves to protect and provide nutrients to the developing embryo. Since the embryo receives no additional nutrients from the hen, the egg must contain all the nutrients essential for life.
Chickens mate when the male mounts the female and they have a 'cloacal kiss' in which the cloaca of both chickens touch for a few seconds. This is sufficient time for the sperm to transfer from the male to the female.
Slide shows from University of Missouri - Learning Reproduction in Animals
Sex reversal in chickens (University of Florida)
Semen collection of the male chicken (University of Missouri)
Early chick embryo development (University of Missouri)
Feather sexing of day-old chicks (University of Missouri)