Do Chickens Need Oyster Shells and Grit? (A Look at What Hens & Other Chickens Require in Their Diet)

Is Oyster Shell & Grit Good for Chickens?

A lot of people think that grit and oyster shells are the same things, but they’re not.

Let’s look at both of these individually to understand their function.


If chickens eat anything other than commercial feed, including bugs, grass, and other small animals, it’s essential that chickens have access to grit (Amazon).

Grit is the term for tiny stones or rocks and is known as insoluble grit. This is because grit doesn’t dissolve in the chicken’s stomach.

Chickens keep grit in their gizzards because it helps them grind up the food they forage in the wild. Because they have no teeth, chickens don’t have a way to properly grind their food without grit.

Without having access to grit, food can sit in the chicken’s digestive tract without progressing and can start fermenting or rotting. This is a condition called sour crop and can be quite dangerous to the chicken’s health.

Sometimes a deficiency of grit can even trigger a digestive tract obstruction. Usually, this is called bound crop and shuts your chicken’s digestion down.

Many people make the mistake of thinking that their chickens will find all the grit they need by picking pebbles off the ground if they’re free-ranging. But some dirt doesn’t have much grit in them.

Even though I let my chickens free-range, I like to give them access to store-bought grit. It’s cheaper and less stressful to buy grit than to have sick chickens.

*Adult chickens who only eat commercial chicken feed (no table scraps or treats) don’t really require grit because commercial feed is soft enough for the chicken to digest.

Grit Size

There are different grades of grit depending on the age of the chicken. Baby chicks should have very fine grit (Amazon). As they get older, the grit should be more coarse (Amazon).

Grit is pooped out as the stones get smaller and smaller inside a chicken. Then, new grit needs to be eaten. If the grit you give them is too small, the pieces will pass right through the chicken’s digestive system. So offering the correct size for chicks or adult hens is important.

Chicks will not initially need any grit until you start feeding them things other than chick feed. I personally do not feed anything other than chick feed to my chicks, but if you do, put a little chick grit over their feet to motivate them to start eating it.

Oyster Shell

High-quality commercial laying feed has a fast-release source of calcium in the form of limestone. However, egg-laying hens tend to need more slow-released calcium than what high-quality commercial laying feed gives them.

Why do they need so much calcium?

Because hens use a lot of calcium to produce eggs.

When an egg-laying hen’s diet is deficient in calcium, she might lay eggs with thin shells or no shells at all.

Also, if a hen doesn’t get enough calcium, this can lead to the calcium from her bones leaching out in order to create eggshells. That may lead to bones that are fragile, deformed, or broken.

Being deficient in calcium might also cause behavior problems like egg-eating since the hens are so desperate for calcium.

If a calcium deficiency becomes a problem, a supplemental source of calcium should be provided, such as crushed oyster shells (Amazon).

Oyster shell is a soluble grit.This is because the calcium from the oyster shell dissolves in the hens’ stomach and is used in making eggshells and strong bones.

You should only start feeding your flock oyster shells if you have hens that are currently laying eggs. Chicks, older hens (non-laying), roosters, and chicks do not need any oyster shells added to their diet.

Should I Mix Oyster Shell With Chicken Feed?

Too much calcium can be harmful to a chicken’s health. So the best way to feed oyster shells to chickens is to serve it in a feeder that’s separate from the chicken feed.

I repeat. Do not mix oyster shells in with the chicken feed!

A layer that needs extra calcium will eat the oyster shell while the other chickens will just ignore it.

Do Chickens Need Grit if They Have Oyster Shells?

The answer is yes, chickens still need grit even if they have oyster shells available.

First, if chickens aren’t deficient in calcium, they will refuse to touch oyster shells for their own safety. Too much calcium can cause kidney damage, egg binding, bone abnormalities, metabolic issues, and more.

Second, oyster shells will not help chickens in breaking down their feed.

So, even though you may be providing your birds with oyster shells, don’t forget to give them access to grit as well.

Conclusion: How Do You Feed Chickens Oyster Shells & Grit?

Offer grit and oyster shells in separate feeders, separate from your chicken’s regular food, so they can eat as much or as little as they need. By giving your chickens the opportunity to peck at oyster shells and grit-free-choice, you’re helping them stay healthy and happy.

Offering grit free-choice provides what your chickens need to properly digest their food.

Also, offering oyster shells free-choice is a great way to ensure your chickens have access to the calcium and other minerals they need for strong bones and to facilitate egg production.

´╗┐Finally, it’s important to note that you shouldn’t feed chicks and other non-laying poultry any oyster shells as too much calcium can cause health issues.

But, typically, if a chicken doesn’t need oyster shell or grit, it won’t eat it unless it’s mixed in its feed (which is just a bad idea).