Home Range collagen flattened jerky is a single-source protein treat that provides essential nutrients, vitamins, and minerals. Collagen is found below the top layer of skin (two layers below the tough outer layer used for leather, upholstery, and notably rawhide) and is a key element in connective tissue. Collagen is like a glue that holds things together. A 100% digestible treat, collagen flattened jerky treats are 84% protein. Rated as a medium-hard chew.