Our supplier says “Liver is a nutrient dense “super food”. It’s rich and easily digestable protein, yet low in calories and packed with essential vitamin and minerals, such as Vitamin A, Vitamin B12, riboflavin, folate, iron, copper, and choline. Most pieces are approximately 1-2 inches long, though there will be some variation in length and thickness. Sources from free range, grass fed, American Bison.” We recommend these tasty, crunchy treats for all dogs!