My boys will chew the bark, sometimes the wood a little, and sometimes they make spears out of them. When they're done with them they either throw them out of the cage (directly in front of my bedroom door, not pleasant to step on first thing in the morning) or they will bury them in the hay that they pull out of the hay holder. Sometimes I'll find the spears while I'm cleaning cages, shoved under the edge of the fleece in their hidey house. I'm fairly certain they are plotting an attack and hope that one week I'll forget to clean or something and they'll be able to stockpile enough weapons to take us down.