I don't know if anyone else has ever done this, but with my first dog I ever had, she'd start chewing on something... say an old rag. Well, I thought it would be okay for her to chew on that. Little did I know she didn't know the difference between an old one and a new one. Or say an old sock and a new sock, what have you. But I learned, so just make sure you don't let your pup chew on anything that you don't want her to be chewing on, regardless of age.