I have two guinea pigs and they love climbing, exploring, and getting under and on top of things. Because of this, I decided to build them a second level. It is really small and not meant for extra space, but it has shade over it so they love sleeping on it and jumping up when they popcorn. However, recently, one of them has stated chewing on the bars up there. She doesn't do it anywhere else in the cage, or when shes out in the play pen, though she is a play pen escape artist. I blocked the side she was chewing with some cardboard, but she just either pulls it off or chews the other side. Is she doing this because she thinks the second level is too small? If so, I've been thinking about buying her another and putting them side by side. Thanks!