Chick grit is tiny, ground up granite. They eat the grit, the grit goes to the gizzard. When the food goes from the crop to the gizzard it gets ground up by the grit. Since chickens don't have teeth, the grit acts like teeth. When your chicken grows up, it will either pick up gravel from the ground or you will need to give them a larger size grit. It is not expensive. Grit for chickens is not added to the food but set out in a little dish so they can get it as needed. If you are just feeding chick feed and soft treats like egg or yogurt you won't need it. But you may for other treats. Treats (anything other than chick feed) should make up no more than 2% of your chick's diet.
