You may have already done a good deal of research about the food, housing, and other requirements for keeping backyard chickens healthy if you have laying hens. But have you ever thought about oyster shell?

Oyster Shell: What is it?​

As its name suggests, oyster shells are simply ground-up oyster shells. It is possible for commercial oyster shells to contain other types of shells, but most of the time, bags labeled "oyster shells" are just plain oyster shells.

Oyster shells have a high calcium content and are also known as soluble grit.

If you have chickens that lay regularly, such as every day or every other day, then they will require even more oyster shell than those that lay just a couple of times a week since calcium carbonate composes 94 to 97 percent of an egg, which has to come from your chickens' bodies.

Although oyster shell will benefit most chickens, not all of them will require it. For example, it is probably not necessary to feed oyster shell to hens who have not yet laid eggs. Accordingly, laying hens will benefit from the following:

  • Eggs are less likely to break
  • Bone damage is reduced
  • Enhances blood vessel strength
  • Enhances the immune system of your chickens
  • Enhances cardiovascular function
Unlike most other species, hens are highly sensitive to nutritional deficiencies. They need access to plenty of calcium in order to make strong eggshells.

Alternatives to store-bought oyster shells?​

There are several alternatives to oyster shell that you can feed your laying hens if you don't want to purchase commercial oyster shell.

1. Eggshells, ground up and cooked​

Feeding eggshells back to chickens may seem gruesome, but it's a great way of recycling old shells and providing your girls with calcium. You should not feed your chickens full eggshells, as this might cause them to eat their own eggs - this is a bad habit that is hard to break if they get into it.

Some people believe that feeding eggshells back to chickens could lead to bacterial infections. You shouldn't have to worry about bacteria infecting your chickens if you cook your shells down before grinding them into a powder.

Additionally, crushing the shells makes them less identifiable, so the chickens won't try eating them.

Keep in mind that if your chickens' diet is already low in calcium, their eggs are not as likely to have high calcium levels. In order to get your hens back into fighting shape, you may need to feed them the crushed eggshells of other birds.

The other small issue with using eggshells in place of oyster shells is that eggshells don't contain the same fast-release calcium source as oyster shells. Although they are still beneficial and a good source of calcium, you will need to be much more consistent about feeding them if you plan to use them as a calcium source.

2. Feeds high in calcium​

There are some layer feeds that contain enough calcium to provide your chickens with what they need. Additionally, there are commercial feeds that are higher in calcium to meet this need.

If you have a mixed flock of chickens (one that includes laying and non-laying chickens), you should avoid feeding this type of feed because it contains too much calcium for the non-laying bunch.

Choose a layer feed that contains at least sixteen percent protein and higher amounts of calcium. You can give it to your hens when they are about 18 weeks old or whenever their first egg is laid, whichever comes first.

It's important to remember not to feed layer feed to birds that don't require it.

3. Crushed limestone​

Commercial laying feeds often contain this type of calcium, but it can also be purchased separately. You should be careful which type of limestone you feed, however, as dolomitic limestone contains a large amount of magnesium which interferes with calcium absorption.

4. Oyster shell feed made at home​

The price of bags of ground oyster shell is relatively low at feed stores, but you may decide that you want to make your own oyster shell supplement. In most cases, this isn't a feasible option - buying oysters just to turn them into feed isn't worth it (unless you really love oysters).

Nevertheless, if you have access to large amounts of free oyster shells, then this can be a great way to save money on your overall feed bill. You should check with your local restaurant to see how they dispose of old oyster shells.

Most of the time, they just throw them away. It might be possible for them to save them for you at no extra cost.

To prepare the shells, bake them in the oven for 10 minutes at 250 degrees Fahrenheit. This can be done on a baking sheet. By baking the shells, mold and other pathogens will be destroyed, and they will also be easier to crack and work with.

After the shells are baked, put them in a bag. Break up the shells by smashing the bag with a hammer or even driving over it with your car. It won't take long at all. After that, you can put the shells in a food processor to make a powdery supplement. Then you are done!

5. Table Scraps​

Your hen's calcium intake can be boosted with several common household foods. In addition to providing a more well-rounded, easily digestible treat, scraps will benefit all of your chickens - not just the layers. Listed below are some high-calcium options:

  • Spinach
  • Swiss chard
  • Mustard greens
  • Kale
  • Yogurt
  • Dandelion greens
  • Red clover
  • Broccoli
  • Brussels sprouts
  • Cheese
  • Milk
  • Basil
  • Cooked beans
  • Cabbage
  • Summer squash
  • Garlic
  • Orange juice
  • Shellfish
  • Salmon and sardines

6. Vitamin Supplements​

It won't necessarily increase your chickens' calcium levels, and it shouldn't be viewed as a solution to calcium deficiency on its own. You can, however, improve your chickens' ability to absorb calcium by supplementing them with vitamin A, D, and E.

You can purchase these supplements in powder form and should add them to their water every other day. Additionally, they won't harm non-laying birds, so you don't have to worry about providing separate watering systems for roosters or young chickens.

How Do I Know If My Chickens Need More Calcium?​

Those who are new to raising chickens may think that they can get by on the feed you buy at the local feed store. Although this is usually true, your chickens might need additional calcium if they exhibit any of the following symptoms.

  • Soft Eggshells: It's time to add calcium to your chickens' eggs if the shells are soft, squishy, or nonexistent. A hen needs a calcium-rich diet to lay a hard-shelled egg.
  • Bone damage: In the last few weeks, has a hen broken a bone or sustained a joint injury? Calcium deficiency may be to blame. If a hen does not have enough calcium while making an eggshell, she will take it from her bones. As a result, she will develop osteoporosis and have trouble standing.
  • A decrease in egg production or failure of your hens to lay eggs: Have your hens reached the age at which they should be laying eggs? Have they stopped laying (or slowed down)? This may be due to a lack of calcium.
  • Lameness: Too little calcium may not cause bone damage in chickens with lame or stiff legs. It is important to remember that these early signs could also symbolize calcium deficiency in non-laying chickens.
  • Behavioral Problems: A low level of calcium may lead to pecking and increased activity in chickens. Some of your flock may suffer serious injury or even die as a result.

How Often Do Chickens Need To Be Fed Oyster Shells?​

If you want your laying hens to have free choice access to oyster shell, leave a bowl or a detached feeder out. Adding oyster shell to feed is possible, but chickens who do not need it may consume too much calcium. The best course of action is to let the birds regulate their calcium intake on their own.

Put oyster shells in a bowl and place it alongside the chicken feed. Hens figure out how much and when to eat on their own. When it runs out, simply refill it.

Regardless of the season or weather, oyster shell should be fed consistently throughout the year. You should continue to feed oyster shell to your hens even if they stop laying while molting, broody, or taking a break during the winter. As a result, their bones will be strengthened and they will be able to lay stronger, more numerous eggs later in the season.

The digestive tract of a chicken takes 90 minutes to pass food. Your hen will quickly absorb calcium into her bloodstream once she is awake and eating.

An egg takes a hen roughly 25 hours to make (there is some variation between breeds). Therefore, she should have regular access to calcium so that her body can always produce a hard shell.

How much nutrition does oyster shell have?​

Your chickens need calcium for laying healthy eggs, and oyster shell is a good source. Hens with low calcium levels are more likely to lay soft-shelled eggs and to suffer from broken bones, particularly in the legs and feet.

Calcium carbonate is the main component of eggshells. In order to produce a healthy eggshell, almost all the calcium must come from the diet of the hen. To obtain the two grams of calcium needed for an eggshell, she should consume approximately four grams of calcium daily.

Larger hens require more calcium.

Your chickens' bodies break down oyster shell into calcium and carbonate components in their intestines after consuming. After being absorbed into the bloodstream, they will be transported to the shell gland, with any leftovers being stored in the bones of the bird.

Hens have a unique type of bone called the medullary bone, which stores calcium, making them stronger and more stable.

Is oyster shell good for chickens that haven't begun laying eggs yet?​

There is no need to worry about feeding oyster shell to the following kinds of chickens:

  • Chicks
  • The pullets that have not yet laid
  • Older chickens that have stopped laying eggs
  • Roosters
In the event that you have a mixed flock of birds, separate your oyster shells so that those who need them can access them and oyster shell will not be overfed to birds who are not in need of it. Small amounts of extra calcium will not harm these chickens, but too much can be harmful.

Too much calcium may have some of the following side effects:

  • Kidney failure
  • Inability to absorb calcium over time (due to an overloaded system)
  • Abnormalities of the legs
  • Issues related to metabolism
  • Vitamin D and phosphorus absorption issues
  • Egg binding
  • Problems with the joints
Until your hens are 18 weeks old, do not feed them oyster shell. Only hens that lay eggs should be given oyster shells.

You should also remember that your hens will only eat as much calcium as they need, so if you mix calcium into their feed before they are ready for it, it can damage their kidneys.

Oyster Shell vs. Grit: What's the Difference?​

Most people (incorrectly) believe oyster shell and grit are the same thing and produce similar results in their backyard flocks of chickens.

They are both essential to your birds' health but are not the same. In the absence of either, serious health conditions may arise, affecting the health and welfare of your flock.

Grit:​

Poultry grit helps your chickens digest their food. Chickens don't have teeth, so they need a way to reduce the particle size of their food so that it is easier to handle. Your chickens consume grit and it passes into the stomach. There it stays for a while, waiting to be worn down enough to pass through the digestive tract of the chicken safely. While it's there, it grinds food into a paste.

After the hen has absorbed all the water and nutrients she needs from the feed, she will poop the paste out.

Chickens benefit from grit because it transforms food into something that is easier to digest and used by the body. Your chickens will have a hard time digesting food if they don't have access to grit, either in a supplemented or natural form. Grit can be bought at the feed store. Basically, it's just flint or granite chipped up. It's economical and doesn't expire.

If your chickens are free-ranging, they should get all the grit they need, but this will depend on your soil type and how much open space you provide.

Oyster Shell:​

The reason oyster shell and grit are often confused is that oyster shell is often called soluble grit. This compound dissolves rapidly in the hen's digestive system and is stored to be used later to make eggshells and support the overall health of your flock. Grit is insoluble, but oyster shell dissolves in the gut.

Despite its digestive benefits, it is primarily intended to add calcium to the diet of your laying hens.

So what's the bottom line? While oyster shell and grit are both necessary for your chickens' health, the two serve very different (yet essential) functions.

Oyster Shell: Why It Is Important​

Calcium deficiency is not just bad for your chickens - it's bad for you too. When you keep laying hens, it is undoubtedly for consumption (or for sale) of the eggs.

In order to prevent bacteria from entering an egg, the shell is the best protection. A strong eggshell will be much more likely to withstand outside pressures, whereas a weak one will be prone to carry diseases.

The last thing you want to do over breakfast is to think about that!

Consider laying down some oyster shell in a separate dish the next time you're in your chicken coop. The hens will appreciate it!

Do you feed Oyster Shell to your chickens?