There are different health and medical issues for each species of pet bird you can think of. When purchasing a new bird, talk to a veterinarian to find out what concerns are particular to your bird. Knowing what to look for with common diseases can help manage an illness, should it arise.
With the larger birds of the parrot family (the parrot, the cockatoo, the macaw), feather picking is one of the more common health problems. Birds that are stressed, anxious, lonely or bored will start picking at themselves and pulling out their feathers. This obsessive behavior shouldn't be confused with the natural loss of feathers that will occur through molting. Sometimes the picking can be controlled with the use of bad tasting substances sprayed on the feathers (such as Bitter Apple) or even collars that prevent the bird from pulling its feathers. These help the symptoms but not the cause of the problem. The bird's living environment should be examined to help ease stress, or alleviate boredom.
The rest of your home can have an impact on the health and well-being of your pet bird. Many bird species are sensitive to toxins in the air and can become quite ill from things you might not suspect. Appliances that have non-stick coatings give off fumes when heated that are very dangerous to a bird. Not just frying pans, but also bread machines, waffle irons, regular clothing irons and even blow dryers. Pesticides, cleaning solutions, and other such volatile products should be avoided in the home.
Your pet bird can suffer from malnutrition if not fed a proper diet. Pelleted products or bird seed mixes are usually designed for a particular bird species and should be used correctly. Your parakeet should not be eating cockatoo bird food. Supplementing a bird food diet with fruit and vegetables is always a good, healthy idea. The bird feeder should be kept clean as well.
Psittacosis is one particular bird disease that should be watched for, namely because it can be transferred from bird to owner. The disease is caused by the Chlamydia bacteria (not the same strain that causes the sexually transmitted disease) and is most often seen in parrots, though it can strike many other species of birds. Symptoms in birds include lethargy, eye discharge, diarrhea and fluffed up feathers. In humans, you can expect flu-like symptoms with fever and chest pains. When seeing a doctor with these rather general symptoms, make sure to inform him or her that you have a pet bird so that Psittacosis can be tested for. The treatment of the disease is antibiotics.