Grit is a finely ground hard substance that is given to chickens to aid in their digestion). Chickens do not have teeth to grind down their food, so they need grit to help them digest their food. Grit is stored in their gizzard, and when the gizzard contracts, the grit helps to crush up the food pieces, making it possible for chickens to digest their food. There are two types of poultry grit: oystershell grit and flint grit. Oystershell grit is a type of calcium that helps make eggshells stronger, while insoluble grit, also known as flint grit, helps chickens with digestion. Insoluble grit consists mainly of crushed stone, such as quartz, granite, feldspar, and phosphate rock, and does not dissolve in the birds digestive system. Instead, it remains in the gizzard for weeks or months to help the bird grind up its food for digestion).

Chickens need grit because they do not have teeth to grind down their food. When left to forage over a larger area, chickens naturally pick up grit in the form of tiny pebbles. They store grit in the gizzard, and when the gizzard moves, the food is ground with any grit inside. The food, now a paste, can then pass safely through the digestive tract. In most cases, backyard chicken owners limit their flock’s foraging to keep them safe from predators. Even with free-range chickens, a piece of land may not have enough of the right kind of small pebbles to help chickens with digestion. It’s a good idea to offer some grit to help a flock.

Types of grit include:

• Soluble grit: This dissolves in a birds digestive system and is usually made from calcium-high materials. The calcium helps the bird in eggshell production. Soluble grit can be made from limestone or coarsely ground or broken seashells, like oyster or mussel shells. Other uses for shell grit include protecting plants from slugs or snails and for aquariums).
• Insoluble grit: This consists mainly of crushed stone (though often with additives) and does not dissolve in the birds digestive system. Instead, it remains in the gizzard for weeks or months to help the bird grind up its food for digestion. Stones used may include quartz, granite, feldspar, and phosphate rock. Insoluble grit is found in the gizzards of birds that eat plant parts and some that eat invertebrates. Because of its grinding function, this kind of grit is sometimes called "hens teeth").

Chicks do not need grit as long as theyre only on chick starter. Once treats are added to their diet, a small bowl of sand can be added to their brooder.