Thank you KevinD and Sukie...In nature, at 5, they are still helping with the family and learning how to be an adult. A Grey matures between 5-7 years old. I would never breed a Grey before 6 years old. At this time, they are finding out stuff about their body and interests they didn't know, or weren't aware of. This is also the time where they reach out, exploring boundaries and expanding their personality. This is a period where a lot of Greys change favorites among their flock (you, your wife, your children, your dog ).
Between now and 8 years old, you will see a lot of changes. Some Greys stop talking and whistle more, some will develop interests like music, looking out windows, calling your dog, cat, or you to see your reaction, and some will have a complete personality change. They are also really learning how to talk. You'll notice at times that your Grey, while you are talking to someone else will be just looking at you or you will walk by the cage and hear them mumbling sounds. What they are doing is learning and practicing how to say words with their beak.
At this time, they will also go to the limit, push outside the box, and destroy the box in an effort to get a reaction out of you. Unfortunately, if our reaction is wrong, we are stuck with this bad habit. (They own us...) Unfortunately also, sneak attacks are very common at this age. The best thing to do is ignore, don't react and praise positive behavior through positive feedback and treats. Remember, we live with them, not the other way around. They own us....