The bill is used to find food, pick it up, and ready it for swallowing. Since birds have no teeth they either swallow the food whole, or bite, crack, or tear it into bite-sized pieces. They often hold the food with their feet as they work at it with the bill.
Birds prepare the food before eating by removing hulls from seeds or inedible parts from prey.
Instead of chewing their food, they swallow it in pieces and it is ground up in their gizzard. The gizzard is a muscular organ just past the stomach. It has a hard, ridged inner surface. Birds swallow grit, sand, and small stones. These stay in the gizzard and are ground against the food to break it up.