What makes hens need calcium? A lack of calcium can lead to weakened eggshells, which means the eggs are more likely to be broken during transport.
In addition, a lack of calcium will weaken bones and make breaking them easier.
The good news is that you don’t have to worry about this happening because you can easily provide your hens with enough calcium to lay healthy eggs – and to stay healthy themselves.
Here’s what you need to know.
Why Do Hens Need Calcium?
Chances are, even if you’re new to raising laying hens, you’ve seen the bags of crushed oyster shells hanging out in the poultry section of your local feed store. But why are they there?
The thing is, calcium is an important part of a laying hen’s diet. Just like you need calcium to help grow strong, healthy bones and prevent breaks and fractures, so does a hen.
However, calcium is important in one other way – it helps chickens lay eggs with strong, healthy shells.
The creation of eggshells is one of the most important reasons you need to supply your laying hens with calcium.
Did you know that an eggshell contains about 90% calcium? When a hen lays an egg every other day (the average for most breeds), she’ll need a ton of calcium to replace what is lost in the production of the new egg.
She’s making a brand new egg every 48 hours, after all!
Without enough calcium, all kinds of problems can arise, including laying eggs with misshapen or deformed shells – or even laying eggs with no shell at all!
Hens Need Calcium for Healthy Bone Development and Growth
In addition to needing calcium to produce eggshells, chickens also need calcium to maintain their bodies.
This is why a hen deficient in calcium may not even show symptoms with her egg production at first – the symptoms might manifest elsewhere as the body robs the hen’s calcium reserves to produce eggs.
Calcium helps with all of the following in a hen’s body:
- Maintaining a proper internal pH
- Controlling and moderating heart rate
- Absorbing and utilizing phosphorus
- Controlling muscle spasms (particularly the muscles that are needed to lay an egg)
- Trigger hormone production and regulate the reproductive system
- Producing eggs that will result in healthy chicks (if allowed to mature)
- Blood clotting
- Maintaining a healthy nervous system
- Activating digestive enzymes
- Ensuring proper bone development and growth
As you can see, calcium isn’t just a bonus in a chicken’s diet – it’s essential for keeping a laying hen healthy!
The Science Behind Why Hens Need Calcium
So you understand now that calcium is important for a laying hen – but do you know why?
Here’s some more information on how calcium really works in the body of a laying hen.
When calcium is absorbed through a hen’s diet, it is stored in the medullary cavity, located in the bones. When the creation of an eggshell calls for more calcium, the nutrient is released into the bloodstream.
The kidneys stop excreting extra calcium and instead conserve it to replace what is released into the bloodstream.
Then, calcium is drawn from food to replace the depleted calcium. The ovaries release estrogen, signalling the hen’s body to produce more medullary bone to store extra calcium.
This cycle sounds complicated and lengthy, but it occurs every day, day in and day out.
A hen needs to consume adequate amounts of calcium each day to create an eggshell and meet the demands of the rest of her body.
It is also important to note that calcium is not a one-person band.
Phosphorus and Vitamin D
It does not act independently to produce a healthy hen but instead requires two other nutrients to make a difference – vitamin D and phosphorus.
Phosphorus and calcium need each other to both be metabolized individually by the body.
Because phosphorus binds to calcium, an imbalance in calcium leads to an imbalance in phosphorus and vice versa.
Like calcium, phosphorus is also essential in the development of healthy bones and indigestion and pH balance.
The good news is that phosphorus is a nutrient in which a hen is rarely deficient. Most grains naturally contain a lot of phosphorus, and the average hen is fed many grains.
The only situation that might lead to a prosperous deficiency is if you feed your laying hens a mostly plant-based diet.
Vitamin D is essential if calcium and phosphorus are both going to be metabolized.
Vitamin D regulates how much calcium is released into the bloodstream to produce eggshells.
It also regulates plasma calcium in the blood and determines if more calcium needs to be released from the bone cavities or stay put into helping strengthen the bones.
A fat-soluble vitamin, vitamin D, is stored in the liver after being consumed via a diet. It is necessary to metabolize phosphorus and calcium.
How to Tell if Hens Need Calcium
All hens need calcium – but if you aren’t sure whether your hens are getting enough from their feed alone, you may want to consider these signs of calcium deficiency.
A deficiency can still arise even if hens are being fed a supplement.
More often than not, this is due to age, environmental factors, or poor health.
You might suspect a calcium deficiency if you notice any of these problems:
- Soft or thin eggshells
- Eggs that are laid without shells
- Poor skeletal development in chicks
- Rickets (also signals vitamin D deficiency)
- Feather loss
- Egg eating
- Feather loss or pecking
- Egg binding (since calcium also controls muscle)
What is the Best Feed to Give Laying Hens?
Laying hens should be fed a complete feed, formulated either as a pellet or crumble.
Choose a feed meant for laying hens, as it will include supplemental calcium (though you should still provide an additional supplement).
The exception is if you are raising roosters with your laying hens.
In that case, a regular ratio is necessary to prevent toxicity – more on this below.
Make sure your laying hens are fed chicken feed with at least 16% protein to ensure adequate growth.
What is a Good Source of Calcium for Chickens?
Now that you know everything there is to know about the science behind calcium and why your hens need it, here are some of the best options for supplying calcium to your chickens.
Whichever option you choose, provide free-choice supplements in a separate treat dispenser or feeder.
They will stop by and nibble on the calcium as needed.
You don’t have to worry about them overdoing it!
Oyster shell is one of the most common ways people give their hens calcium.
You can purchase crushed oyster shells at your local feed store, typically sold near the layer feed.
When buying oyster shells, consider the particle size.
Most are finely ground down, so they are small enough for the hens to consume but not so small that they pass right through the digestive tract.
Particles about the size of a pea or larger are ideal – the longer the particle stays in the digestive system, the more calcium can be absorbed.
Of all the calcium supplements you can give your hens, oyster shells tend to stay in a hen’s system the longest, maximizing the potential for calcium absorption.
Another option is to give your hens crushed eggshells.
As with oyster shells, you need to make sure the shells are the right size.
In this method, you’ll dry used eggshells and crush them up.
They can then be fed back to your hens.
These make a good supplement in addition to crushed oyster shells, but they don’t stay in the digestive system very long.
A final option to consider when providing your hens with supplemental calcium is to use chipped limestone.
Chipped limestone isn’t as commonly fed as a calcium supplement since it’s harder for a hen to absorb it.
It moves through the digestive system very quickly, and depending on the source of the limestone, the calcium content can vary.
Tips for Determining How Much Calcium Your Hens Need
Each hen will have her own individual requirements when it comes to how much calcium she needs.
The best way to provide calcium is to offer it a free choice – that way, all of your birds can help themselves whenever they want it.
Provide supplemental calcium regardless of whether it is included in the feed.
When attempting to figure out how much calcium your laying hens need, consider the age of your birds first.
Older hens need more since their bones have been depleted of nutrients for so long.
Hens fed a less-than-balanced diet – such as one with too many treats – may also need more calcium.
Hens with good layers, including egg-laying breeds like White Leghorns and Golden Comets, will need more calcium.
The more often a hen lays, the more she needs calcium to produce those strong shells!
Similarly, hens of poor digestive health (such as those recovering from a parasite infestation) or poor health, in general, need more calcium.
Individuals who suffer from liver and kidney problems need more calcium since their absorption of vitamin D and phosphorus is more limited.
Of course, consider the season and weather, too. In the spring and summer, calcium needs will be higher since hens are laying more eggs.
Hot weather also makes it more difficult for a hen to absorb calcium to need additional supplementation.
What About Phosphorus and Vitamin D?
In addition to calcium, it’s a good idea to provide your laying hens with vitamin D and phosphorus, too.
You can supplement these two nutrients by providing quality layer feeds. However, certain snacks can increase your hens’ ability to process calcium during high-laying periods.
You might give treats like
- Black soldier fly larvae
- Sprouted sunflower seeds
- Cooked eggs (don’t feed raw, as this can encourage egg eating behavior)
- Meat and fish
Do Chicks Need Calcium?
Baby chicks do also need calcium to develop strong, healthy bones.
However, you should not provide supplemental calcium or feed a layer feed to these young animals.
Too much calcium can be detrimental for young chicks under 18 weeks of age.
Keep calcium at a rate of 1% or lower for young birds and wait to switch to a layer feed until they are at least 18 weeks old.
Do Roosters Need Calcium?
As with chicks, roosters need a small amount of calcium to grow healthily.
However, it would help if you were careful about feeding roosters layer feed or any supplemental calcium.
This is because roosters aren’t laying eggs and therefore don’t need as much calcium as laying hens.
Too much calcium can cause severe kidney damage and impact rooster fertility. It can even lead to premature death.
Therefore, stick to a fee with higher protein and less calcium while also feeding roosters.
Too Much of a Good Thing: Can Hens Have Too Much Calcium?
Can hens have too much calcium?
Yes – but this isn’t nearly as common as a calcium deficiency.
A hen who has an overabundance of calcium will have symptoms such as hard deposits on eggshells.
They look like little bumps.
They may also suffer from hypercalcemia.
Again, this is rare and causes the kidneys to calcify and can also cause liver damage.
Calcium overdose rarely occurs unless a hen suddenly stops laying but continues to consume a supplement.
If you own hens, then it’s important to give them calcium.
Without enough of this mineral in their diet, your animals will suffer from many health problems and might not live as long or be able to produce eggs at the appropriate rate.
To avoid these issues for yourself and your flock, ensure they’re getting an ample supply of calcium-rich foods such as kale, spinach, broccoli leaves (a favorite among chickens), almonds, sesame seeds, cheese, and yogurt.
Of course, oyster shell is the most common calcium supplement for hens, and it’s the easiest to feed out, too.
Make providing a bit of oyster shell part of your weekly feeding schedule.
As always with animal care – if you have any questions about how much calcium is safe for a hen or when it should receive it – consult a veterinarian before proceeding!