Why chooks need hard grit

Hard grit, such as rocks and pebbles, is essential for healthy hen digestion , yet it’s very rarely discussed. Often confused with shell grit, hard grit is actually quite different. Shell grit is soluble calcium pieces that hens absorb to make eggshells, while hard grit refers to small insoluble stones birds swallow to use for grinding up food. It’s often called digestive grit, and many domesticated birds need more of it.

Role of hard grit

Chooks famously don’t have teeth, yet they eat hard grains and seeds. Hard grit has a pivotal role in breaking down these foods into smaller particles for digestion.
When fowls swallow their dinner, it travels to the crop, where it is stored, moistened and softened, then to the proventriculus or stomach, where chemical digestion begins. It then moves to the gizzard, where the majority of chemical and mechanical breakdown occurs.
To enable this, the gizzard’s strong muscular walls contract and push the grains and fibres against the small stones stored there. Grinding them up like a mortar and pestle.
This grinding process releases nutrients and facilitates digestion, allowing chooks to extract nourishment from their food. While obviously necessary for wholegrains, grass or insects, hard grit also enables better digestion of mash and pellets.
Over time, these stored stones are ground down and pass out of the body, so chooks need a regular top-up supply.

Benefits

Studies have found that ample access to hard grit can improve feed conversion. An experimental broiler group weighed more and consumed less feed when given access to hard grit over nine weeks.
So, providing your chooks with access to small stones can potentially save you money! By allowing your chooks to release more nutrients from food, you’ll be rewarded with healthier birds and better-quality eggs.

Our Early Winter 2026 issue (OG 165) you can learn the best way to ensure your chooks have enough grit in their diets. You’ll find it in newsagents and selected supermarkets. Or you can subscribe here to get an issue delivered to your door!