7 Best Turkey Calcium Supplements For Laying Hens Old Farmers Swear By

You’ve seen it before: you reach into the nesting box and your fingers find a soft, rubbery egg, or worse, a cracked and broken mess. That’s the classic sign of a calcium deficiency, a problem that can plague even the most well-cared-for flock. Providing a reliable calcium source isn’t just about strong eggshells; it’s about the long-term health and bone density of your laying hens. Choosing the right supplement means navigating a market full of options, from classic oyster shells to modern, all-in-one formulas.

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Manna Pro Grit: For Digestion and Calcium Boost

Manna Pro’s offering is a common sight in feed stores, and for good reason. It combines two essential needs into one bag: insoluble granite grit for grinding food in the gizzard and soluble oyster shell for calcium. This two-in-one approach is incredibly convenient for the busy farmer. You put one feeder out, and you’ve covered both bases.

The tradeoff for that convenience is a lack of specialization. Because it’s a mix, it’s not as calcium-dense as a pure oyster shell product. If you’re dealing with a flock that has persistent thin-shell problems, you might find they aren’t getting a concentrated enough dose.

Think of it as a great starting point. For a healthy, young flock on a quality layer feed, Manna Pro Grit is often all you need. But if you start seeing issues, you may need to supplement with an additional, pure calcium source.

Purina Oyster Shell: A Classic, Reliable Source

This is the old standby, the one your grandparents probably used. Purina Oyster Shell is exactly what it says on the bag: crushed oyster shell. There are no other additives, no extra vitamins, just a straightforward, effective source of slow-release calcium carbonate.

Its simplicity is its greatest strength. By offering it free-choice in a separate container, you allow each hen to regulate her own intake. A young, high-production hen will take what she needs, while an older hen slowing down might consume less. This self-regulation is crucial for preventing over-supplementation, which can cause kidney issues.

Remember, this is only a calcium source. You will still need to provide insoluble grit separately, especially if your flock doesn’t have regular access to sandy or gravelly soil. Don’t make the common mistake of assuming oyster shell handles digestion—it dissolves in the gizzard and doesn’t help grind feed.

Grubblies Grubs: A Natural Calcium-Rich Treat

Dried black soldier fly larvae, like Grubblies, have become a hugely popular treat for chickens. Hens go absolutely wild for them, and they offer a fantastic protein boost. They also happen to be naturally high in calcium, with a much better calcium-to-phosphorus ratio than mealworms.

Let’s be clear: this is a treat, not a primary calcium source. While beneficial, relying on grubs alone for calcium is an expensive and unreliable strategy. The hens might not eat enough to meet their daily needs, especially high-production layers.

Use grubs as a supplement to their diet and a boost to their overall health. Tossing a handful out in the afternoon provides enrichment and a nutritional kick. Just make sure that a separate dish of regular oyster shell is always available so they can get the consistent, slow-release calcium they truly need for shell production overnight.

Scratch and Peck Oyster Shell for Organic Flocks

For those running an organic operation or simply committed to an all-organic feed program, Scratch and Peck is the go-to. Their oyster shell is OMRI Listed, meaning it’s approved for use in certified organic agriculture. You can feed it with confidence, knowing it meets those stringent standards.

Functionally, the product is very similar to conventional oyster shell. It provides the same slow-release calcium carbonate that hens need. The primary difference is the sourcing and processing that allows it to be certified.

Is it necessary for the average backyard flock? Probably not. If you aren’t concerned with organic certification, a standard oyster shell from a reputable brand like Purina or Nutrena will do the job just fine. But if maintaining a fully organic system is your goal, Scratch and Peck is the correct and necessary choice.

Kalmbach Hen-Hancé: A Complete Supplement Mix

Kalmbach takes a different approach with Hen-Hancé. This isn’t just calcium; it’s a comprehensive supplement designed to be mixed into feed. It contains oyster shell and limestone for calcium, but also includes probiotics, prebiotics, and essential oils to support gut health and immunity.

This "kitchen sink" method is perfect for the farmer who wants to ensure all nutritional bases are covered without having multiple supplement containers. It simplifies feeding and can be a great boost for flocks during times of stress, like molting or extreme weather.

The downside is that you lose the benefit of free-choice supplementation. By mixing it into the feed, you’re deciding how much calcium each hen gets, rather than letting her self-regulate. For most flocks this is fine, but it can be less precise than offering oyster shell on the side. It’s a fantastic product, but it represents a different philosophy of supplementation.

Nutrena Oyster Shell: Coarse Grade for Big Layers

Not all oyster shell is crushed to the same size, and that matters. Nutrena’s product is often a coarser grade, with larger, chunkier pieces. This can be a significant advantage for certain flocks.

The larger pieces take longer to break down in the hen’s digestive system. This provides a slower, more sustained release of calcium into her bloodstream, which is particularly beneficial overnight when most of the eggshell is formed. This makes it an excellent choice for:

• Heavy breeds: Orpingtons, Brahmas, and Wyandottes can handle the larger pieces easily.
• High-production layers: Hens laying daily have immense calcium demands.
• Flocks with chronic shell quality issues: A slow, steady supply can make all the difference.

If you have bantams or smaller breeds, they might ignore the larger pieces. It’s all about matching the supplement to the birds you’re raising.

Small Pet Select: Finely Crushed for All Hens

On the other end of the spectrum, you have finely crushed options like the one from Small Pet Select. A finer grind makes the calcium more accessible to a wider variety of birds. Bantams, smaller breeds like Leghorns, and even younger pullets just coming into lay can find it easier to consume.

A finer product is also great for mixed flocks where you have a wide range of bird sizes. The big girls and the little girls can all get what they need from the same dish. The only potential issue is that the fine particles can sometimes turn to dust at the bottom of the feeder or get kicked out and wasted more easily.

This is a great all-purpose choice, especially if you’ve noticed your hens are hesitant to eat a coarser shell. Sometimes, just changing the texture is enough to encourage better consumption and improve shell quality across the entire flock.

Thomas Labs Fish-Cal: A Powdered Calcium Option

What do you do when your hens just won’t touch oyster shell? Some picky flocks will ignore it completely, no matter the size or brand. This is where a powdered supplement like Thomas Labs Fish-Cal, made from fish bone meal, can save the day.

Because it’s a powder, you can mix it directly into their feed, ensuring they consume it. It’s an excellent way to deliver calcium to stubborn birds. It can also be added to wet mashes or fermented feed, which can be particularly helpful for a hen that is recovering from an illness or injury.

The key here is dosage and control. Unlike free-choice oyster shell, you are in charge of how much they get. You must follow the package directions carefully. Giving too much calcium can be just as harmful as giving too little, potentially leading to kidney damage. This is a problem-solving tool, not a standard daily supplement for a healthy flock.

Ultimately, the best calcium supplement is the one your hens will actually eat, and the one that fits your management style. There’s no magic bullet, only careful observation. Start with a classic free-choice oyster shell, watch your eggshells and your birds, and don’t be afraid to try a different texture or a new product if you aren’t getting the results you need. A small dish of the right stuff, always available, is one of the cheapest and most effective forms of insurance for a healthy, productive flock.