These are a couple of old articles but I thought you would like to hear about Cocky Bennett, a lesser sulfur that lived to be 120 years old even though they thought he had PBFD. He was taken out of the wild when he was a baby and that, most likely, and the fact that he lived in captivity in the same country he was born in (think natural diet!) is what made his longevity possible. Now, personally, if I couldn't find a way to trim his beak or make his life better, I would have put that poor bird down way before he got to that venerable age... but that's me.
https://earthlingnature.wordpress.com/2 ... ld-legend/
http://www.smh.com.au/environment/anima ... 1jkz2.html