tho geared towards greys this site talks of diseases. Diseases cross species and are not species specific.
The Grey Roost
some times babies are vaccinated. Depending on the breeder and bird, and against certain diseases. Some vaccinated birds should not be housed with unvaccinated birds. Perfect example.....
Avian Polyomavirus
Eclectus parrots and Caiques NEVER outgrow the risk of Polyoma, while other species are most affected under the age of 2 years old. Greys have been noted to outgrow the risk over 2 years of age.