Barkworthies, 3 Pack, 6", 95 Percent Collagen Beef Sticks Dog Treats. These scrumptious beef sticks are 100 percent natural. Contains 95 percent collagen to support your dog's well-being from the inside out. Collagen is known to help promote mobility and flexibility, help relieve joint pain and stiffness, and support skin, coat and digestive health. Made without grains, so sidekicks with certain food sensitivities can enjoy them, too! Crafted with limited ingredients.