Due to the number of species it is best to give just a few general comments. Make sure seed-eating birds have access to grit – they need this for their gizzard to break up the seeds to release nutrients. Also make sure they have different sized perches. Because captive birds spend more time on their feet than wild birds, they are prone to pressure necrosis or “Bumble Foot” – by having different diameter perches the pressure will be distributed over different areas of their feet.
Another problem can be “Psittacosis” or “Ornithosis” which is caused by Chlamydia. Birds can develop respiratory signs (a bit like influenza) which can be passed to humans – especially those that might be immunosuppressed. It is important to see a vet as soon as possible and also to be careful with your own hygiene around the bird. Birds will often not show they are sick until they are very ill. When unwell they appear “fluffed up”, but they often revert to normal when in the presence of people, even their owners! The best way to look for this is through a window or from another room!
Do check your bird’s nails and beak regularly. One of the most common problems is “feather plucking”. This can be as a result of many different things – some medical, others behavioural, but most commonly it is stress. This may be because the bird is left alone too much or doesn’t have enough privacy – it is very akin to us biting our nails. Whilst trying to work out the cause of the problem you can lightly mist the bird with a fine mist of water using a plant spray gun (make sure there are no chemicals in it!). This will leave very fine water droplets on the feathers and the bird will have to spend more time pruning this out and hopefully less time pulling the feathers out.