Hello beautiful! Redbarn's Beaut-A-Bulls collagen collection is 100% natural, sourced from bovine collagen, transforms chew time into your dog's spa day. Collagen is a protein found below the top layer of skin in both animals and humans. It is one of the key components of connective tissues. Naturally rich in chondroitin and glucosamine, these chews support healthy joints, healthy skin, and beautiful, shiny coats.