Grit for Chickens: Why the Gizzard Needs Stones
TL;DR: Chickens have no teeth. The gizzard grinds food against hard particles the bird swallows — that is grit. Birds on commercial crumble or pellets alone generally do not need it, because there is nothing to grind. Birds eating grain, greens, scraps or forage do. Offer it free-choice in a separate container from feed and from calcium, because grit and oyster shell are different materials doing different jobs.
Simple, cheap, and the reason a flock on kitchen scraps can be underfed while eating plenty.
How a Chicken Digests Without Teeth
Food goes down whole. It is stored briefly in the crop, then passes into the gizzard — a thick, muscular organ that contracts hard around whatever is inside it.
If the gizzard contains hard particles, food gets crushed and ground between them. If it contains nothing hard, a whole grain of maize stays largely a whole grain of maize.
So grit is not a nutrient. It is a tool the bird keeps inside itself, and it wears down slowly and needs replacing.
Who Needs It, and Who Does Not
| Diet | Grit needed? |
|---|---|
| Commercial crumble or pellets only | Generally no — already ground |
| Whole or cracked grain (maize, palay) | Yes |
| Kitchen scraps and greens | Yes — see kitchen scraps for chickens |
| Free-range and foraging | Yes, though birds usually find their own |
| Homemade rations with unground components | Yes — see homemade chicken feed |
| Chicks on starter crumble only | Generally no |
| Chicks eating anything else | Yes, chick-sized |
Free-range birds normally pick up their own grit from the ground as they forage. The exceptions worth watching: bare compacted ground, permanently muddy ground, paved runs, and ground that has been worked over by birds for years. Offering grit free-choice costs almost nothing and removes the question — see free-range native chicken farming.
Grit Is Not Oyster Shell
The distinction that catches people out.
| Grit | Oyster shell | |
|---|---|---|
| Dissolves? | No | Yes |
| Job | Grinding in the gizzard | Calcium for eggshells |
| Who needs it | Birds eating unground food | Birds in lay |
| Harmful to non-laying birds? | No | Yes, in excess |
Oyster shell dissolves, so it cannot stay in the gizzard to grind. Grit does not dissolve, so it supplies no calcium. Offer both, in separate containers, when both are needed — see oyster shell and grit and calcium for laying hens.
How to Offer It
- Free-choice, in its own container. Birds take what they need; you cannot calculate it for them.
- Separate from the feed and from the calcium container.
- Keep it dry. Wet, caked grit is not eaten.
- Correct particle size for the bird: chick grit for chicks, larger for adults. A particle too large is not swallowed; too small does not grind.
- Top it up. Grit wears down and passes through, so it is consumed continuously.
What Goes Wrong Without It
Poor digestion. The bird eats and gets less from it. This shows as poor condition on what looks like adequate feed, and it is easy to blame on the feed instead.
Impacted crop or gizzard. In severe cases, fibrous material such as long grass accumulates and blocks. A bird with a swollen, hard crop that does not empty overnight is a case for your agrivet — related to but different from sour crop.
Wasted feed money. Buying grain and having a share of it pass through undigested is an expensive way to save on a bag of grit.
Practical Notes
- New birds coming onto scraps or grain should have grit from the start, not after they have been on it for weeks — see quarantining new birds.
- Confined birds are entirely dependent on you for it. A bird in a layer cage or a gamefowl in an individual pen cannot forage for stones.
- Long, fibrous greens are the material most associated with impaction. Chop them, and make sure grit is available.
- Do not substitute fine sand, wood ash or soil. Grit is sold for the purpose and is cheap.
The Honest Limits Here
The role of the gizzard in mechanical digestion, and the need for insoluble grit in birds consuming unground feed, are established poultry physiology. This guide gives no quantities, because grit is offered free-choice and birds regulate their own intake. Particle size should match the bird’s size — ask your agrivet which product is which, since grit and calcium supplements can look similar in the bag. A bird with a hard, non-emptying crop needs veterinary advice rather than more grit.
Related: oyster shell and grit, kitchen scraps for chickens, types of chicken feed, homemade chicken feed.
Frequently Asked Questions
What is grit and what does it do?
Hard, insoluble particles that a chicken swallows and holds in its gizzard, where muscular action grinds food against them. Chickens have no teeth, so this is how whole grains and fibrous material are broken down.
Do all chickens need grit?
Birds eating only commercial crumble or pellets generally do not, because that feed is already ground. Birds eating whole grain, greens, kitchen scraps or anything foraged do need it.
Is grit the same as oyster shell?
No. Grit is insoluble and stays in the gizzard to grind. Oyster shell dissolves and supplies calcium for eggshells. They do different jobs and are offered in separate containers.
Do free-range chickens need grit provided?
They usually pick up their own from the ground, but ground that is bare, muddy, paved or heavily used may not supply enough. Offering it free-choice costs little and removes the doubt.
Do chicks need grit?
Chicks on commercial starter crumble alone do not. Once they eat anything unground, they need chick-sized grit — smaller particles than adult grit.
Can I use sand instead?
Fine sand is not a substitute. Grit needs to be hard particles of a size the gizzard can hold and work against.
What happens without grit?
A bird eating unground food digests it poorly, so it gets less from the same feed and can lose condition. In severe cases undigested material can accumulate and cause an impacted crop or gizzard.