Nikko and Pepper love peanuts. Equivalent to Amy’s Kong, we have a peanut holder for the birdies, that stimulates them and they play around with it to get to the yummy nuts. Pepper usually tries to reach and grab with her beak, and uses one of her legs to hold it steady, while she works her way through.
Nikko gets really excited when he sees peanuts even before I get to put them in the toy. He runs around the cage, trying different ways to get to them. His best shot on it is by hanging upside down. I will go for anything that keeps him busy.