Before I had my FN, I had one of those collapsible cages. In that cage, he decided to try chewing the bars for attention. Without realizing the consequences for my actions, I would give him the attention he craved. After I learned to sleep through the chewing of the bars, he learned to SHAKE THE ENTIRE CAGE! It was so loud I wanted to die. He had food, water, hay, toys, everything he needs, and it was always between 2-3 am, and I had school at 6! When he moved up in the world into his FN, it became silent compared to the noise he used to make. I didn't even realize that he was chewing them until I felt the bars. SIGH! Anyway, back on topic, he is doing it for attention. My chinchillas have no problems with their teeth, so I wouldn't be concerned with it. I've tried specifically ignoring him when he does chew the bars to try to un-learn that chewing does not equal attention, but the opposite.