When I was in Vet. School, I volunteered in the Avian nursery. We would hand raise several types of psittacines, and once weaned and well socialized, we would send them on to the people who purchased them.
We had several birds that were donated by people who had bought them, not realizing how long they really live, only to have to will them to the school when they died. We had a 50year old African Grey that we recieved that way, sweetest old bird.

The first Clinic I worked at, after Vet school, had a couple that would board their 2 Cockatoos with us. Those 2 birds would argue back and forth for hours, in their owners voices and rather colorful language. Most entertaining birds I've ever seen.