For profitable poultry production (as well as a 'happy' flock) it is important to maintain a healthy flock. The well-known quote "The best defense is a great offense" holds true when keeping poultry. A strong biosecurity program is important to keep disease-causing organisms (bacteria, viruses, fungi, etc) away from your flock.

To understand the effects of disease-causing organisms (and management problems) on the health of your flock it is important to have a good understanding of the anatomy and physiology of poultry and what the inside of a healthy bird looks like.

Avian necropsy techniques (University of Florida)

The most popularly known poultry disease is Avian Influenza.

Sticky droppings: A feed-related problem (Washington State University)

Common poultry diseases (University of Florida)

A variety of leg disorders are possible in poultry flocks. They can be the result of improper nutrition and/or management. Some problems are genetic. Leg problems can be a problem in chicken flocks raising Cornish-based chicks for meat production (i.e., broilers) because of the potential for them to put on weight faster than they can develop the bone structure to support the weight. Waterfowl, turkeys, and game birds are prone to leg and foot problems

Eye disorders (not related to disease) are not very common in poultry flocks. Birds rely on their sight in order to find food and water so any problems with their vision will adversely affect flock performance.