Pile of Crushed Pellets?

I've noticed that my female chinchilla tends to have a pile of crushed pellets next to her food dish. She's eating the same amount as always (about a tablespoon a day) and I feed the Oxbow pellets. She doesn't eat hay - I still give it to her. She only eats the bark off of the sticks, and doesn't chew on her ledges. I'm wondering if this is something I need to keep an eye on or a hint that she might have a tooth issue? She's about 2 1/2 to 3 years old. I had posted previously about her being underweight when we first got her and started tracking her weight. We've since stopped as she looks and feels healthy. She has a metal Flying Saucer that she runs on every day.



Any thoughts? Is this normal?



Thanks!