Visible Signs of illness to be aware of are
Weight loss / lack of appetite
Partially closed or watery eyes, closed eyes or swelling of the eyelids
Respiratory symptoms, such as rasping noises, difficulty breathing
Ruffled plumage (feeling unwell, cold)
Drooping wings, sagging body, falling off perches (weakness)
Bulges in feathering (tumors?)
Excessive saliva (toxicity?)
Dirty vent (indicative of diarrhea)
Any change in the feces not apparently diet related
Behavioral: Listlessness or extreme mood changes
MACAWS ARE PARTICULARLY SUSCEPTIBLE TO THE FOLLOWING DISEASES & HEALTH PROBLEMS
Avian Bornaviral Ganglioneuritis (PDD)
Psittacine Beak and Feather Disease, PBFD, Beak and Feather
Psittacosis (chlamydiosis or parrot fever)
Respiratory Signs, Chronic Depression, Weightloss: Aspergillosis (fungal disease), bacterial infections / pneumonia, nutritional deficiencies (Hypovitaminosis A), Psittacosis / Parrot Fever, and inhaled toxins
Chronic Sinus Infections: increasing humidity and using air filters may help minimize the problem.
Sunken-Eye Syndrome: Caused by sinus infections. The eye sinks into the socket.
Herpes Infections: May cause proliferative lesions, but more commonly exemplify itself by depigmentation (loss of color).
Feather picking (various behavioral as well as physical reasons can be the cause - boredom, but also heavy metal toxicity, giardia, bacterial / viral diseases)
Toxicity - heavy metal poisoning
Allergies
Coacal Papillomas: Thought to be a viral condition. Contagious to other birds (thought to be sexually transmitted). Affected birds should not be used for breeding.
Kidney disease (gout) - May be caused by excessive supplementation of Vitamin A.
Lipomas (tumors) in older birds
Macaw "Acne": Small swellings on face caused by small, ingrown feathers on face and eyelids, simple surgery to release trapped feathers; antibiotic injections, cortico-steroids needed if bird rubs and scratches affected sites.
Beak malformations in chicks (improper feeding technique?)
Annular Toe Lesions: Seen in chicks, may result in loss of toes.
Miscellaneous Infections: Bacterial, viral or fungal
If you notice any sign of illness, it is important to provide supportive care until a pet can be taken to a veterinarian for assessment and treatment.