Our bones are from 100% natural, grain-fed, steroid-free, hormone-free, livestock. Dogs' natural desire to chew on bones comes from the fact that they are carnivorous canines 99.9% similar to wolves. In the wild, wolves kill their prey and chew on bones—so dogs chewing on bones is only natural, compared to highly-processed and highly-chemical rawhide chews, bones are all-natural! This whole, unprocessed food works with dogs' bodies and doesn’t contain unnecessary chemicals or preservatives—the only preservative is the freezer!