A study shows the need for our captive African Greys to have access to ultraviolet light in order to keep calcium at normal levels, if vitamin D isn’t appropriately provided for in the diet. This is one of the reasons why they are prone to calcium deficiency disorders (the symptoms of which can be seizures and other neurologic abnormalities, bone misshapenness, feather picking, and many others).
Many AG’s come in with bowed tibiotarsal bones due to calcium disorders that happened when they were a chick; these bones were too weak to support the weight of the heavy bird and the stress caused either a mild fracture in the bone (called a folding fracture- just think of folding a straw how it crimps) or the bone just arched due to the rubberyness; after the initial stress caused the bowing, the pulling and shortening of the tendons down along these bones kept the deformity from straightening out. The bird can’t quite perch as strongly and tends to fall more, and is not as graceful. Victims of this tend to become more fearful and have more behavior issues and I see quite a number become significant feather pickers.
If you would rather get a baby rather than adopting an unwanted older bird, it is best to get your AG from a breeder that pays attention to nutrition of both the parent birds as well as the youngsters. This rewards the breeders that do so, as well as providing yourself with the best chance of a well-adapted happy bird with a lower chance of behavioral problems.
You can keep up your AG’s calcium level by providing a good balanced diet but also by providing a few hours out in the sun a week. Just make sure the bird can’t fly away; provide an option for shade, be careful to ensure that predators can’t get to your bird, make sure the temperature doesn’t get too hot or cold, and don’t go out when biting bugs are outâ€“ but ultimately, be wary of any danger.