Preheat oven to 400°. In a large bowl, combine eggs, bread crumbs, salsa and onion. Add turkey, pork and beef; mix lightly but thoroughly. Shape into 1-1/2-in. balls. Place meatballs on greased racks in two 15x10x1-in. baking pans. Bake until browned, 18-22 minutes., In a 6-qt. slow cooker, combine sauce ingredients. Add meatballs; gently stir to coat. Cook, covered, on low 3-4 hours or until meatballs are cooked through.