You need to plan ahead before you bring a bird into your home.  Part of that planning should include a same-day wellness visit to a reputable veterinarian since there is no way to be sure a bird is completely healthy just by looking at it.  After a physical examination, the veterinarian may discuss screening your new bird with laboratory tests.  Simple tests can be done at the hospital, such as looking at droppings and oral secretions for abnormal bacteria using a Gram stain or checking the droppings for parasites.  However, additional tests are often needed particular for birds that have been around many other birds.  The importance of this additional testing cannot be ignored -- one study using protein electrophoresis, a kind of blood test, revealed that 30% of seemingly healthy birds had undetected infectious or inflammatory disease.  Specific tests for psittacosis (also known as parrot fever or chlamydophilosis), Pacheco's virus, and psittacine beak and feather disease may be important especially if you have other birds at home.  If the Gram stain suggests abnormal bacteria are present then microbiological cultures and sensitivities should be performed so that the right antibiotic can be chosed to treat the infection.  Your new bird can have its sex determined by saliva, blood, or feather samples to confirm that you got what you paid for or to learn what you got.  When you are budgeting for a new bird, make sure you remember to include money for a thorough health check!

As mentioned above, some birds carry infectious diseases but do not appear to be unhealthy.  In some cases, such as sun conures and Pacheco's virus, the disease they have is not harmful to one kind of bird but can be deadly if it gets into another species of bird (such as an African grey parrot).  Birds may also carry diseases that can be passed to people and are called zoonotic diseases.  Psittacosis, also known as parrot fever or chlamydiosis, is one of the best known of these zoonotic diseases.  Ideally your new bird should be kept in a separate room under strict quarantine for 30 to 60 days until all the labwork has been analyzed and you are sure it is healthy and maintaining or gaining weight.

If your new bird (or any other birds in your house) show any signs of sickness, such as fluffed feathers, sneezing, poor appetite, or watery droppings, you should immediately get it to a good bird veterinarian.  A delay of more than a day can spell the difference between life and death for many diseases.  If you start to have a headache, fever, scratchy throat, congestion, or other signs of illness shortly after bringing a new bird home, call your doctor.