When a distressed bird is taken to an avian veterinarian, respiratory disease is often found to be the cause. Frequent sneezing, nasal discharge, periocular swelling, coughing, wheezing, and a voice change may be evident. Dyspnea, or labored breathing, may be seen at rest or after the bird flies a short distance.
Poor nutrition is a major factor in the development of respiratory tract disease.
Vitamin A is essential for the health and integrity of the epithelial lining of the respiratory tract. Hypovitaminosis A, a deficiency in vitamin A, leads to changes in the respiratory epithelium which allow bacteria, virus, and fungi to invade the body. Poor nutrition also affects the immune system, further weakening the normal protective defense mechanisms of the avian repiratory tract. Respiratory signs are not always the result of disease of the respiratory tract. Other disorders may mimic respiratory tract disease.