Wood toys are very important to keep in a cage. Cavies love to chew on things and what else more convenient than wood? It keeps in control their teeth growth and in some kind of way it keeps them relaxed and entertained. always make sure to check the wooden toy to see if there are any pieces missing (not to worry) but he could be missing out his favorite hobby (chewing) replace the wood toy if you see it is completely damaged as it could loose up parts and injure your cavy. Always change the position of the toy so your cavy can take advantage of the whole toy :D. Other acceptable toys are gourds, cholla wood, or mineral blocks. These toys can also help your cavy's overgrowth of teeth. If you have other questions feel free to reply the Mods. and I can help.