Crumps' naturals Gutsy Immune Bites. Gutsy Immune Bites help reinforce your dog’s immunity with gut boosting prebiotics in every bite. Formulated with science backed ingredients like fermented yeast and powerful prebiotics to help naturally occurring good gut bacteria thrive. These tasty bites are designed to enhance immune response with functional mushrooms like Chaga, Lion’s mane, Shiitake and Turkey Tail, ensuring your pet's well-being from the inside out. Why? Because over 70% of your immune system lives in the gut! Healthy Gut = Healthy Body = Healthy Mind. Made in Canada Available Sizes: 4.6 oz (130 g) / 10 oz (284 g).