[cypher]

They do get some odd little habits sometimes & it doesn't necessarily mean they're bored or there's a problem to worry about, they often don't chew wood or toys sold as chew toys though so you could try her with a whimzee dog chew, the small toothbrush one is best, she'll probably love that!
Keeping her in cardboard boxes sounds a bit worrying though, she could probably chew through them & all cages need a lid really, escapes & other accidents happen all too easily without one.