A chicken gizzard is located in the digestive tract and sits above the stomach of the chicken. The chicken gizzard exists to help grind up the food the chicken eats for easier digestion.
The gizzard of the chicken is a tough and rubbery organ. It can be eaten, but it is tough to chew. The gizzard is made up of very powerful muscles and is able to accomplish a grinding motion that makes things such as hard grains of rice and kernels easier to digest. The gizzard works in combination with small pellets of debris and stones the chicken picks up while eating food. These pellets get stuck in the gizzard and work with the gizzard to help grind the food.
Not all birds have gizzards, but the birds that have them use them to their full extent. Turkeys are able to grind steel needles with their tough gizzards. An owl gizzard is a special organ that is only present in birds of prey. The gizzard breaks down the feathers, fur, bones and teeth of the prey. The gizzard works with the stomach acid to grind the materials and form a hard pellet, which is then regurgitated before the owl eats again.