Animal hooves, antlers, and bones: Hard animal parts and particularly cooked bones pose the most significant risk to your dog's teeth and GI tract because they are very hard and indigestible. If your dog doesn't break a tooth first, he could manage to snap off a piece and ingest it. Some animal horns (like buffalo or goat horns) soften and fray a little while dogs are chewing them. These can be less dangerous to the teeth and may be more easily tolerated by the GI tract. However, they should be used with extreme caution.