Animal by-products are materials derived from animals that are not intended for direct human consumption. These can include parts like bones, feathers, and organs, which are often used in various industries. For example, gelatin is made from animal collagen and is commonly found in food products, while leather is produced from animal hides. In addition to food and clothing, animal by-products are also utilized in non-food items. For instance, animal fats can be used in the production of soaps and candles, while blood meal serves as a high-nitrogen fertilizer in agriculture. These by-products help reduce waste and maximize the use of animal resources.