Chickens rely on a powerful muscle called the gizzard to grind their feed. To make this internal mill work, they need to swallow tiny, sharp stones known as digestive grit. This is an insoluble grit, meaning it stays intact and does not dissolve in their digestive tract. Excellent natural options include crushed granite, flint, or coarse river sand.
Size is very important when providing grit. Just like their daily feed, the stones need to match the age and physical size of the bird. Chicks require a very fine grit similar to sand, and the size should increase as they grow.
When chickens are free ranging, they usually find enough small stones naturally. However, if your property has heavy clay or mostly muddy soil, there might not be enough sharp, durable stones available for them. Nowadays most commercial feeds are already ground and made into pellets to increase absorption. But since most chickens still enjoy kitchen scraps, grass, bugs and more, providing a small dish of commercial granite grit will certainly help ensure everything they eat is properly processed.
For the little ones in the brooder, commercial chick starter is specially formulated to break down easily without any extra help. But the exact moment we introduce anything else to their diet, like a clump of grass, scrambled eggs, or any treats, they instantly need access to chick sized grit to process that new food safely.
And as a gentle reminder, soluble options like crushed oyster shells are wonderful for providing calcium for strong eggshells, but they are simply too soft and dissolve too quickly to help with digesting food.
