You can add a multivitamin to the water until your bird is getting enough vitamins from fruits and vegetables. Most vitamin supplements have a dextrose or sugar base. Birds are naturally affectionate, active and intelligent. They make excellent pets. They are extremely hardy and can survive harsh living conditions.
Many birds appear active and healthy even after being on an all-seed diet for years.
The truth is, though, they are actually suffering from malnutrition. A bird suffering from malnutrition will eventually die from organ failure or from secondary bacterial or viral infections that plague a compromised immune system. Your avian veterinarian can assess the health of your bird through annual physical examinations and routine blood testings. Changing your bird's diet from seeds to a more nutritional one requires patience, persistence and time.