My one girl chews the cage bars furiously when I am getting her veggies ready...and the younger girl is now doing it as well (monkey-see, monkey-do!) and I would put plexiglass on the side she does it the most, but she does it in whatever area she's in when she hears the food sounds. Is it damaging for their teeth to do this? If not, I guess I am not worried about the cage itself. I just don't want them to damage their teeth.