These bison marrow bones from Winnie Lou – The Canine Co. will keep your dogs happy for hours! The bones are slow-roasted for over 40 hours at a very low temperature, ensuring that the perfect amount of moisture is maintained during the process and strengthening the bone to prevent splintering and breakage. No other ingredients are added! No spices, no salt, no rubs, no smoke, no charcoal; there’s nothing harmful or toxic in their preparation. Your dogs will love their snacks, and you’ll love Winnie Lou’s commitment to making healthy treats for pups. Bones come in two sizes.