Grit For Chickens (How Much, Why They Need It, How To Feed)

The idiom, as rare as hen’s teeth, means something is extremely rare or nonexistent. Humans and many other animals have teeth to grind food before swallowing, but what if you only have a beak? Many birds and some reptiles have devised an ingenious system to grind their food inside their stomachs, but for the process to work effectively, they need a plentiful supply of grit.

Chicken grit is small non-digestible stones that chickens need to aid digestion. Granite is commonly used to make commercial grit. The hard stones are stored inside the gizzard and pulverize fibrous food to make it more digestible. Grit is not the same as oyster shells or eggshell calcium supplements.

If you are new to keeping poultry, you may wonder if grit is necessary since it has no nutritional value. Let’s learn why chickens need to eat tiny rocks and how many they require to process their food effectively.

What Is Grit For Chickens?

Many bird species use grit as a tool to aid in crushing and grinding hard and fibrous food inside their gizzards. Since they don’t have teeth to break down food as it is taken in, they consume small amounts of fine stone to get the job done further along in their digestive tract.

Chicken grit is an insoluble assortment of tiny rocks, which in commercial mixes usually consists of granite and flint. It offers no nutritional value but is invaluable inside the bird’s gizzard, where it helps to mash up tough food until it’s fine enough to be digested.

There is often confusion about what grit is and what form it should take. Many chicken owners erroneously believe that feeding oyster shells or crushed eggshells serves both purposes; chickens get the grinding stones they require along with a healthy dose of calcium.

Unfortunately, that is not how it works, and all chickens need non-digestible rocks to break down their other food. Insoluble grit is required by chickens of all ages, including roosters, while calcium-rich supplements like crushed eggshells are only needed by laying hens.

Soluble grit may look like hard bits from the outside, but it is quickly dissolved by the bird’s system. Unlike insoluble grit, it is a dietary supplement intended to provide calcium to hens so they can produce strong-shelled eggs. Soluble grit is not effective as a digestion tool for chickens.

Insoluble grit serves an entirely different purpose than soluble grit. The table below is a comparison of insoluble and soluble chicken grit.

Insoluble GritSoluble Grit
Made from flakes of granite or flintMade from oyster shells, eggshells, or limestone
Entirely non-digestible and will eventually make its way through the bird’s systemDigestible and will be crushed in the gizzard
Provides no food nutrients to the birdIt provides a rich supply of calcium carbonate
Required by all chickens regardless of age or sexOnly required by laying hens
Chickens require very little grit.Hens may require more calcium-rich grit.
Both are inexpensive and must be fed in free choice feeders away from the staple chicken food.

Can Chickens Eat Too Much Grit?

When provided with a free choice feeder containing only grit, chickens rarely consume more than they need. It is never a good idea to mix grit, even soluble calcium supplements like oyster shells, directly into a chicken’s staple food.

A chicken knows when it needs to add a few more rocks to the collection in its gizzard. When it has enough and everything is working perfectly, it will abstain from taking in more grit until it needs more.

Young chicks may occasionally take in more fine grit in the form of sand than they should. This can result in an impacted crop, as grit should only be consumed in moderation as a digestion aid and not as food.

chicken grit

Do Chickens Need Grit?

Chickens that only eat commercial poultry foods may not require additional grit as it dissolves quickly and doesn’t require additional processing to make it finer. However, that is not the kindest or best way to keep chickens, as it runs contrary to how their digestive system is designed to work.

Any chickens that are free-range or receive other food in addition to processed commercial food require grit. Even young chicks that are given snacks in addition to their grower mash can benefit from being provided with sand grit.

There is a common belief among many poultry owners that free-range chickens don’t require additional grit since they can pick up tiny pebbles while they are foraging. While that is true to a large extent, collecting sufficient stones off clay soil or during winter when there is ice and snow on the ground may be impossible.

Grit is inexpensive, so keeping a well-stocked, free-choice feeder on one side of your coop won’t break the bank. The birds will be able to help themselves throughout the year and be able to comfortably digest any tasty snacks that come their way.

Why Do Chickens Need Grit?

The short answer to why chickens need grit is because they don’t have teeth. While humans grind food at the top of the digestive system, most bird species perform this function further along their systems.

When chickens snack on something like tasty green grass, they break off the blade with their beak and send it on its way. The next stop is their crop which is like a large food storage bag. The crop moderates the speed at which food moves through to the next stop, which is the gizzard.

The gizzard is where the insoluble grit is required. Since grass is a tough fibrous plant, it arrives in the gizzard in a similar form to how it was ingested. Food is pulverized using a combination of grit and muscle movements, making it easier for the bird’s system to exact nutrients.

True chicken grit is not digestible. Although eggshells and oyster shells are often referred to as soluble grit, it doesn’t work as a food digestion aid in the same way as granite or flint grit. They are calcium sources that are invaluable in the diet of laying hens, but since it is broken down and absorbed by the gut, it does not perform the same function as true grit.

When the grit in a bird’s system becomes worn down, it moves on through the system and is passed out in droppings. The chicken will then ingest more suitable grit to restock its gizzard.

How To Feed Chickens Grit

Grit should always be provided in a free choice feeder away from where chickens receive their staple food. It is a digestion tool, not a treat, so they won’t tuck in greedily; they will only take as much as they require.

Keeping a designated hopper filled with grit slightly away from their feed makes it easy always to have it available to the flock. Insoluble grit is inexpensive; chickens only use small amounts, so one bag can last a long time.

Soluble grit in the form of crushed oyster shells or eggshells should be provided in a separate free-choice feeder. It is only necessary for coops with laying hens, and they will help themselves when they feel that they require a calcium boost. It is unnecessary to provide calcium-rich soluble grit in coops with hens before they start laying.

chickens eating eggshells

How To Make Grit For Chickens

Insoluble chicken grit is not expensive, and one bag goes a long way. Remember that it should never be mixed with poultry food, as chickens will pick out tiny stones to consume when they need them to aid digestion.

You can create your own insoluble grit for your chickens by supplying them with a few shovelfuls of tiny stones or pieces of gravel. There is no need to sieve it as the chickens will select stones that are the right size.

Coarse sand can serve as grit for young chicks, but it must be kept away from their food in case they get confused and consume too much. As the birds grow, they will require larger rocks to help their gizzards grind up hard and fibrous food.

It is advisable to purchase commercial grit as it is guaranteed to be free of contaminants and is more likely to be the right size for chickens. Since grit acts as the chicken’s teeth, it is a valuable component in ensuring good digestive health.

Why Do Chickens Eat Rocks?

Like many birds and other animals, chickens eat rocks to help grind up their food inside their mechanical stomach organ, called the gizzard. Rocks that have been inside an animal and used for digestion are called gastroliths, which means ‘stomach stones.’

Besides chickens, other animals that need rocks to aid digestion include alligators, crocodiles, ostriches, and toothed whales. Many species of dinosaurs required gastroliths to process their food, supporting the view that chickens are mini-dinos.

Chickens don’t eat rocks like they would eat other food. Grit is swallowed rather than eaten. The small stones are not digested and only stay in the bird’s system as long as they are big enough to grind the hard seeds and fibrous food in the gizzard. The stones eventually pass through the system, and the bird needs to swallow more grit to take its place.

Chickens eating grit

Do Chickens Need Grit If They Are Outside?

Chickens that free-range often find their own supply of grit while foraging. If they require grit in their gizzards, they will readily pick up and swallow any suitable tiny stones that they happen upon.

Although free-range chickens are more likely to find their own grit, it isn’t always guaranteed. Chickens in areas with clay soil or regions that experience heavy snowfall may struggle to find suitable grit to power their mechanical stomachs.

Since grit is inexpensive and only needs to be provided in a free choice feeder, it makes sense to keep a supply available even if your chickens are free ranging. It is highly likely to go down a lot more slowly than in coops where birds are confined, but having insoluble grit available at all times ensures that they have everything that they need to be healthy close to home.


Insoluble chicken grit should be supplied to poultry as a free-choice item at all stages of their lives. Both hens and roosters need insoluble grit, and it is not a food supplement. The tiny stones work as tools inside chickens’ gizzards to grind hard and tough food.

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