I've been trying to make homemade toys and I have no idea if my bird are eating or tearing them up. I made him a necklace with all sorts of button and a seashell or two. I've been watching him chew on the seashell and even break off pieces of it. After be breaks them, he chews on the small broken pieces like a pellet. After he chew, those small pieces break into dust-like shards. I do not know if he is spitting them out or if he thought they were his pellets and ate them. How can I tell if he knows not to eat a certain material? Should I let him continue playing with the necklace?