They need to are actually fairly hard dogs as I haven't found a Canine ruin one of those. But to anyone who has defied the extremely hard, I recommend the aptly named Kong Serious. Disclaimer: This website has affiliate and/or referral links which may or may not produce revenue in https://garretteawqk.blogunok.com/36476024/not-known-facts-about-toy-dog-for-sale