Rawhide is a by-product of the leather industry, which means it’s difficult to digest and often treated with harsh chemicals you don’t want your dog to consume. Collagen, in contrast, is a type of protein that is easily broken down by your pet’s digestive system. In fact, it’s a metabolic “building block” that’s naturally found in your dog’s skin, fur, bones, tendons, cartilage, gut lining, nails and more.