For this recipe you can use beef, pork, bison chicken, or turkey. They all work beautifully and if you'd like you can use a combination of meats. The key is in the fat content of the meat you are using. We like a 80/20 grass fed ground beef. Chicken and turkey tend to be leaner, so your meatballs may be a bit drier. Add grated zucchini or diced mushrooms to add moisture.