He had been parent-raised for his first sixteen days. His parents were in a cage over a tray of walnut shell bedding that was thought to be out of reach, due to a cage bottom grill. That is as close as the young one got to the bedding. So please, don't risk your bird's life. Not just babies eat cage bottom materials.
Adults can, and do, as well.
And birds of all ages can die from that behavior. Plain old newspaper, paper towels, brown paper bags, etc., work just fine. You can see and evaluate daily droppings, catching any changes before the problem is overwhelming. Color, size, consistency and number of droppings are all VERY important. OR NOT All the bird books tell us that avocados and parsley are toxic and that if our birds eat them, they might die.