A treat widely accepted by most birds and Parrots.

Millet seed is a good source of magnesium and phosphorus. It is good for birds and people, as it is high in silica content, which is important for the nervous system tendons, skin and nails.  

Hang in the cage or weave the stalks through the cage bars. There's a mutlitude of ways to offer millet sprays to make feeding interesting for the bird.