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Feeding Oyster Shells To Your Chickens (Ultimate Guide)

oyster shell for chickens

In this article we go over in detail the reason why or why not you may want to feed oyster shells to your chickens. We discuss why chickens need certain supplements and what the best oyster shells for chickens are.    

Ultimate Guide To Feeding Oyster Shells To Your Chickens

Did you know that a chicken’s eggshell is composed of 94% calcium carbonate? If your hens are not getting enough calcium in their diet, the first place that deficiency is going to appear is in their eggs.

It’s also important to note that the needs for a hen’s calcium goes up when the weather gets hot and as she increases in age. The telltale sign that your chickens need more calcium in their diet is when you start noticing eggs laid with thin, weak eggshells. You might even find one without a shell at all. Before this happens, consider feeding your chickens oyster shells, a natural and tasty calcium supplement that will help keep your hens healthy and their eggshells strong.

Why Do Chickens Need Oyster Shells?

Oyster shells are a natural calcium supplement you can feed your chickens to provide them with the extras calcium they need in their daily diet. Oyster shells are highly recommended by chicken experts like those at McMurray Hatchery. They suggest providing your laying hens with ground oyster shells.

We know their shells are made up of around 95% calcium carbonate, but chickens need calcium for other reasons. In one year, a hen will invest 20 times more calcium into her shells than her bones. Since she diverts so much of her calcium intake into producing shells, we need to make sure she gets enough to keep her bones healthy as well.

Many commercial grains have a good supply of calcium. If your hens forage, free-range, or rely on other sources of food, you definitely should supplement with a source of calcium like oyster shells. Even if you are providing them with a good-quality commercial food, you can give them oyster shells as well. They only eat what they need so there are no worries about giving them too much calcium.

Signs You May Want To Feed Your Chickens Oyster Shell

If you have been feeding your chickens a commercial brand of feed or they are free-range and you notice any of the following problems, you should add additional calcium to their diet.

  • Soft shells: if the eggs are squishy, it’s most likely a calcium deficiency.
  • Bone damage: if your chickens are prone to bone breakage and joint injuries, it could be the result of not enough calcium. Chickens can actually steal calcium from their bones to make eggshells if they don’t have a sufficient source.
  • Reduction of egg production or no egg production: if your hens are still of laying age but have simply slowed down or stopped laying, this may be a calcium deficiency.
  • Lameness: if your chickens are walking stiffly or seem to be limping, this may be an early warning sign of a calcium deficiency.
  • Strange behavior: increased activity, over-pecking, odd behavior, may be signs of calcium deficiency. This can lead to injury and death to your flock.

When to Start Feeding Chickens Oyster Shells

You may have heard the term “grit” when it comes to feeding chickens. Oyster shells are a soluble grit. When eaten, they dissolve in a hen’s gut and are absorbed by the body. They are stored and used as needed to make shells and build and strengthen bones. Just like people, the individual needs for calcium will vary from hen to hen. If a hen is a prolific layer, she will need more than her slacking neighbor. In some rare cases, a chicken can have a shell gland defect which may require them to ingest more calcium than normal.

So, when do you need to start feeding oyster shells? Only laying hens need extra calcium. Chicks, young non-laying hens and roosters do not need oyster shells added to their diet. It’s always best to offer the shells in a separate container as too much can be harmful. If the shells are in a separate container, they will eat them as they need them.

When everyone in your flock is of laying age and laying consistently, that is the time to introduce the oyster shells. Feeding the shells before 18 weeks may cause kidney damage. Remember to keep them separate from the other food and allow them to pick at them as needed. Never combine their regular food with the oyster shells as this can cause the chickens to eat too much which could result in serious health problems.

How To Prepare Oyster Shells for Your Chickens (DIY)

You can purchase ground oyster shells from most feed stores. However, you may be able to get shells from a seafood restaurant or your feed store may sell bags of whole oyster shells for a very reasonable price. If you have a convenient supply of whole oyster shells and want to break down your own, here are the steps to follow.

Instructions for breaking down oyster shells from Wiki How begins with baking the shells to break down any harmful bacteria.

1. Bake raw shells at 250 degrees for 10 minutes. Simply place the shells on a baking sheet. You can crack them into smaller pieces with a hammer to make them fit more easily on the baking sheets.

Baking will kill off harmful mold or bacteria. Even though these may not harm your chicken, it’s better to be safe. The baking process dries the shells out which makes them easier to crack.

2. After the shells cool, load them into an old pillowcase, burlap bag, or feed bag. Tie the sack closed to prevent harming yourself from flying pieces of shell.

3. Use a hammer to smash the shells into small pieces. Make sure to take the bag to a safe spot outside, lay it flat, then bang away with a hammer. The smaller the pieces, the easier it is for the chickens to pick them up. They should be roughly the size of your pinkie nail or smaller.

Don’t like hammering? You can drive back and forth over the bag with your car or tractor.

4. To make the shells into a powder, grind them with a food processor. You should use an old blender or food processor. Dump in the fragments and use the machine to continue breaking them down to a powder.

You don’t have to break the shells down to powder as the chickens will still eat the fragments. Some chicken owners prefer the powder as it is easier to ingest.

How Much Oyster Shell To Feed Chickens

Use A Separate Container

The best method is putting the oyster shells in a separate container and allowing them to “free feed” and eat the amount they feel they need. You can place the shells in a bowl or feeder to provide easy access. As mentioned previously, never mix it with their regular feed.

Refill the Container When It’s Empty.

The birds will self-regulate their calcium needs. tell us that on average, a hen will heat 100 grams of feed a day with about 4% of that being calcium.

Feed Oyster Shells To Your Chickens Year Round.

No matter what the season or weather, your girls will still need their calcium. You can continue feeding calcium through molting season, when they are broody, or even in the winter if they are taking a laying break.

Providing sufficient calcium will keep your girls’ bones strong and allow them to lay a higher number of and stronger eggs when it comes to laying season again.

A Few Facts About Digesting Calcium

It will take around 90 minutes for the shells to pass through the digestive tract. If your hens are awake and actively eating, the calcium will dissolve quickly into the bloodstream.

It takes approximately 25 hours for a hen to create an egg. Having a consistent calcium supply will ensure your girl is always able to produce an egg with a nice, hard shell.

The Best Crushed Oyster Shells For Chickens (And Where To Buy Them)

The best oyster shells for your chickens, if you are not making your own, should be pellet size and be heat treated for purity. You can call around to your local feed stores to see what types of crushed oysters they have on hand. If you find a brand you like, most feed stores are willing to order it if they don’t already carry that brand. They may need a minimum order.

The following are some of the top-rated brands. These can be found at Tractor Supply Co., Agway, Farm and Tractor, and many local feed stores. They can also be ordered through Amazon.

1. Manna Pro Oyster Shell

Manna Pro Oyster Shell for chickens
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Manna Pro Oyster Shell is a proven brand of oyster shells and comes with good customer ratings. You most likely will find a great deal on Amazon as a 5 pound bag of oyster shell is incredibly affordable.

2. Scratch and Peck Feeds – Cluckin’ Good Oyster Shell Supplement

Scratch and Peck Feeds - Cluckin' Good Oyster Shell Supplement
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Scratch and Peck Feeds – Cluckin’ Good Oyster Shell Supplementis a flaked form of oyster shells. This is an easy and convenient way to serve your girls her daily dose of oyster shells. You will pay a bit more for this form, but it is easy to eat and digest. You can order this also through Amazon. 

3. Small Pet Select Oyster Shell for Chickens

Small Pet Select Oyster Shell for Chickens
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Small Pet Select Oyster Shell for Chickens is another popular brand of oyster shells for your chickens because it is a thinner crushed version of oyster shells for chickens. It comes with a 100% customer satisfaction guarantee, so if you don’t like it, you can send it back.

This product has great reviews and is on the pricier side for oyster shells. You can check it out on Amazon for the most current price.

Final Thoughts

Raising chickens is an extremely rewarding farm experience. Your chickens will welcome you each and every day with exuberance for their daily feed and treats. Their antics are never tiring as they love to dash around and have such interesting and varied personalities.

Cracking open a farm fresh egg in the morning, with a firm shell, and a bright orange yoke is like opening a ray of sunshine. In order to keep those shells strong, your girls healthy and happy, you need to feed them a consistent and good source of calcium. Free feeding oyster shells is a great way to give your flock the everyday calcium they need.

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