Using Eggshells as a Calcium Source

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There are many misconceptions out there about feeding chickens eggshells for calcium, so I'll share what I know and you can decide what you'll do.

Note: in this article, when I say "hen" I mean any laying female chicken. Technically, a female chicken is a "pullet" until they turn a year old.


First things first, why do hens need calcium?

A chicken eggshell is 95 percent "calcium carbonate". Calcium carbonate (CaCO3) is made of calcium (Ca), oxygen (O), and carbon (C). Don't worry, the rest of the article isn't this sciency! ;)

Eggshells are the highest natural source of calcium in the world! But think of all the calcium it takes to make that tough shell! Not to mention that chickens need a bit of calcium for their bones too...

If hens don't get enough calcium, their eggshells will get thinner, and they may start having problems such as:

  • Soft-shelled eggs
  • Shell-less eggs
  • Oddly shaped eggs
  • Fairy eggs (aka pullet eggs, rooster eggs, yolk-less eggs, fart eggs, and more)
All the problems listed above have the possibility of turning into egg-binding (also called eggbound hens), which can sometimes be deadly. And all can be fixed and prevented by having more calcium in the hens' diet. (For more info, read Common egg quality problems)

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From left to right: fairy egg, extra long egg, abnormally shaped egg

This just goes to say, monitor your eggs for problems. Also, each chicken will react differently when lacking in calcium. I have one hen who will lay fairy eggs with extra thick shells when she is lacking in calcium, one who's eggshells get super thin, and a couple who lay extra long or pointy eggs.


How do I give them more calcium?
Thankfully, supplying calcium is pretty easy. There are three main ways to do this.

Layer Feed
You can find this at most feed stores. It works great, but if you have roosters or non-laying chicks in your flock, the extra calcium could hurt them. Use this only if you have a flock of laying hens.

Oyster Shells (OS)
You can find this at most feed stores too. Feed it as free-choice along side your ordinary feed and the hens will eat it according to their inner cravings.

I recommend always having a bag of it on hand, even if you use eggshells, for reasons I will state later.

Recycled Eggshells
This is the cheapest and most natural method. My personal favorite! Let's get started...



Methods:
Eggshells can be prepared in many different ways. Because this can sometimes be a hot topic, please listen to this: there is no right or wrong way. Just because somebody doesn't do it the same way you do doesn't mean you get to criticize them for it. We're all in the same world and want the best for our chickens!

One popular concern is that feeding the chickens eggshells will convince them to eat their own eggs. Some people have problems with this, and others don't. But if you are worried about it, the safest method is the baking method, and try crunching up your eggshells extra small.

Air-dry
In this method all you do is let your eggshells dry for a day or two before feeding them to your hens. Eggs prepared like this are often hard to crunch up. This is often combined with Rinsing.

Rinsing
Just rinse your shells in water. That's all there is too it.

Baking
This is the most cautious way, and the safest. Place your eggshells on a cookie sheet and bake them in the oven for five minutes. I recommend putting them in after something else has finished cooking so you don't waste any electricity. Some people do this in microwaves.

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Eggshells fresh out of the oven


Those are the main ways. If you know of amy others, please comment below or send me a PM!


Extra notes:
  • Most (though not all) people crunch up their eggshells before feeding them to the flock. How small you want them is up to you. Some people do them in bite sized pieces, some crumble them to a powder. Others just feed them to their flock whole.
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Crunched up eggshells
  • I wouldn't feed your chickens eggshells from store eggs. These often have chemicals sprayed on them.
  • Chickens can also get calcium from insects.
  • Every once in a while, I feed my hens oyster shells. Think of it this way; a bit of calcium from the eggshells will be saved for the hens' bones, and some will get lost along the way. Over time your recycled eggshells won't have enough calcium in them to support your hens. So I occasionally boost my eggshells with OS.
  • Because of the latter note, you may be thinking "If I am going to use OS anyways, then why bother with eggshells?" Well, eggshells are completely free while you have to buy oyster shells. Would you rather feed your hens oyster shells full-time and pay the cost, or feed eggshells with just a bit of OS in the side?
  • As mentioned before, I recommend feeding eggshells (or OS) as free-choice. The hens will eat it If there bodies are craving it, and the roosters will mostly avoid them. (https://www.backyardchickens.com/threads/cravings-they-are-real.1419990/)
  • Recommended future reading: Eggshells for Laying Hens

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Have fun with your eggshells!
About author
PioneerChicks
The Creative Homesteaders raise and love on chickens, rabbits, cats, and a dog! We love nature and are always- becoming more self sufficient. We breed and conserve endangered heritage breeds!

About myself personally... I've been raising chickens for 10 years and have participated in 4-H since 2017. I love using my chicken knowledge to help other people!

If you have any questions or feedback about my article, please comment below or send me a PM. Don't forget to rate and review!

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A well written article. I am one of those people who have concerns about feeding eggshells to my flock but after reading your methods, I'd feel safer doing it now. The extra links for further reading are helpful too.
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Great article! Very informative.
As a newbie, I hadn't realised that eggs could be made in different shapes and sizes!
I knew that giving eggshells back to the hens was a good idea.
I have been drying out eggshells on top of the stove and crushing them up.
? ? ?
PioneerChicks
PioneerChicks
Yes, eggs are so amazing!
Your method sounds great! Give it a shot!

Comments

Salmonella on the eggshells is a problem for the humans, not for the chickens. Hence why some people bake the eggshells. The more you touch raw eggs and shells, the higher your chance of contaminating surfaces and getting infected - so, to avoid handling them raw (when cleaning, storing, etc.) you bake them first and then do with them whatever you want.

My immune system is fine, but my husband's isn't. He takes immunosuppressant drugs, so I can't risk it. I don't wash the eggshells, because I don't see the point - it won't get rid of any salmonella, and why would I remove egg residue? It's nutritious and would be a bonus for the chickens. What I do is I have a small aluminum pie pan on the counter where I collect eggshells right after cooking. When I have enough, I put the pan in the oven after I've baked something, with the oven turned off. The residual heat is enough to cook the eggshells and kill any salmonella. When they're cooked and cooled down, I crunch them up small and put them in storage (large wide-throat jar). I grab from this jar to refill the chickens' eggshell bowl. The shells don't need refrigeration at this point, so they're easy to store. They're dry, so they won't mold. They're clean and safe for the humans to handle. They haven't lost their nutritious bits of egg, and they're crushed small so the chickens won't make the connection between this and the egg they just laid, so it won't encourage them to break and eat their own (the bits of egg being cooked also helps with this - it's not recognizable as egg to them anymore).

So this is what I do. It's working out great.


So helpful! Thank you
 
Salmonella is an entire genus of bacteria and in general are incredibly common, so common that the source of most infections is never detected. It's quite contagious amongst animals and usually goes the fecal to oral route (ie, food contaminated by feces that is consumed), so if one of your chickens has it...considering the ubiquitous nature of their poo...they're all gonna end up as carriers, so there's really no point keeping your hens from eating each other's egg shells.

That being said, salmonella is more likely to occur in larger poultry operations due to the cramped conditions which is one of the reasons you don't want to feed store bought shells unless you cook them first (as someone pointed out earlier cooking to 165 kills salmonella bacteria).

And of course, always, always, always wash your hands after handling poultry/poultry products and after going to the bathroom. Typhoid fever is caused by a salmonella bacterium (NOT one of the ones chickens can carry, thank goodness) and not washing her nasty hands is why Typhoid Mary will be long remembered.
 
Id think if you are going to store, do not use an airtight container like a bag, that's only asking for mold and mildew. Maybe an old box like a 12 pack cardboard box or something might work better. It lets some air in there to keep the stanky danky's out. I do that with some onions and other foods im prepping to freeze dry and it seems to work well.

Aaron
 
Don't know if I'm doin it right but... I have a new flock. Just got 'em in March of last year.They have been layin since about August. Before they started layin, I made an oyster shell dispenser. Holds about 2 lbs. They have not eaten any of it as far as I can tell, the dispenser is still full. I also feed some of the shells back to them. The rest go to the garden. They eat the shells like they are candy when I put them out with their evening treats. I have never had a weak shell, all have been very strong. They do free range for several hours from about noon until time to come into the run for the evening. This is working for me so that's what I'm sticking with. Hopin I don't have to buy any more OS cause that's one more expense I don't have to deal with!
 
Wolfie they won't really eat the oyster shell like candy or scratch feeds, they'll pick one or two. One thing with getting oyster shells, not only is it calcium, but Id assume the rocks can be used in the gizzard as well, however if yours are able to free range then Im pretty positive they are picking up their own stones and gravel they need for that. You won't need much though, its not like they are going to eat pounds at a time that I have seen. Just sprinkle a few on the ground in their pen by their feed and they'll peck at them when they need them.

My extra shells I just throw in the compost with the rest of the food garbage and they go into the plants.

Aaron
 
Wonderful article! Very helpful and well written!

I was saving egg shells in a zipped up Ziploc bag, in the back of the fridge. After cracking the shells to use, I just put the spent shells in the bag. I stored them here until I needed them and then I'd bake and crunch them up finely. They stored nicely like this because many of the shell halves would fit into each other and save lots of space. Now, onto my question/concern............
When I was ready to bake them, I noticed some mold growing on some of the shells. I don't wash my eggs, unless they are really dirty, and none of them had any noticeable debris. At that time, I was storing eggs in the fridge within a weeks time of being laid. Any idea about what caused the mold to grow? Any thoughts on keeping this from happening, other than baking them within a few days? Also, I was storing the baked/crushed eggshells in another Ziploc in the fridge until my flock started to get low in the coop. Is this necessary or is it ok to keep them in a sealed container on the counter top? Thank you so much! I've had these questions for months now
If the shells have not been washed I think they should be refrigerated because indeed something moldy or otherwise might grow on them. Becomes disgusting and unhealthy for the human as well as for the chickens.
My question is at what age should a pullet be permitted to eat layer and feed and/or shells - due to the risk of kidney issues because of increased calcium mentioned above.
 
Don't know if I'm doin it right but... I have a new flock. Just got 'em in March of last year.They have been layin since about August. Before they started layin, I made an oyster shell dispenser. Holds about 2 lbs. They have not eaten any of it as far as I can tell, the dispenser is still full. I also feed some of the shells back to them. The rest go to the garden. They eat the shells like they are candy when I put them out with their evening treats. I have never had a weak shell, all have been very strong. They do free range for several hours from about noon until time to come into the run for the evening. This is working for me so that's what I'm sticking with. Hopin I don't have to buy any more OS cause that's one more expense I don't have to deal with!

Likewise our chickens had no interest in the oyster shells. I scatter the crunched up chicken egg shells out in the yard when they’re free ranging. And likewise I let them out to free range around noon after they’ve done most of their laying. We still do occasionally get a soft shell.
 
If the shells have not been washed I think they should be refrigerated because indeed something moldy or otherwise might grow on them. Becomes disgusting and unhealthy for the human as well as for the chickens.
My question is at what age should a pullet be permitted to eat layer and feed and/or shells - due to the risk of kidney issues because of increased calcium mentioned above.
I've always thought that they should be offered a source of extra calcium (either with oyster shell or egg shells whether they're being fed layer feed or an all flock feed) once they reach POL. It's not good to start layer feed until they begin laying, if I'm not mistaken. Let's see if a nutritional expert can share more ~ @EggSighted4Life is very knowledgeable about nutrition stuff (among other things)
 
If the shells have not been washed I think they should be refrigerated because indeed something moldy or otherwise might grow on them. Becomes disgusting and unhealthy for the human as well as for the chickens.
My question is at what age should a pullet be permitted to eat layer and feed and/or shells - due to the risk of kidney issues because of increased calcium mentioned above.
@BDutch pointed out that may be a myth. I'm learning more about that right now and will hopefully be able to update soon with more info!
 
@BDutch pointed out that may be a myth. I'm learning more about that right now and will hopefully be able to update soon with more info!

Even if it is a myth, it's definitely true that they don't need extra calcium until they lay, so why risk it? I say use regular feed and provide a free choice calcium source. Chickens are pretty good about getting what they need if you have it available for them.

If the shells have not been washed I think they should be refrigerated because indeed something moldy or otherwise might grow on them. Becomes disgusting and unhealthy for the human as well as for the chickens.

If you give them a good rinse and let them dry thoroughly, there really is no need to store them in the refrigerator. I keep mine in a large jar with a mallet nearby--whenever they get towards the top, I give them a thorough crushing with the mallet. I've never had a problem with mold or smells. I don't put a top on so no moisture gets trapped in there.

We still do occasionally get a soft shell.

Soft shells are not always (at least entirely) caused by lack of calcium. It can sometimes be due to just starting to lay, or an infection in the reproductive tract. You should try to figure out who lays them if you can, just in case, cause she could be doing it more often than you know, it's just the other chickens are eating them.
 
I rinse my chickens eggshells in hot water and lay them on paper towels to dry over night. Then I crush them with my morter and pestle and feed them to the girls. They gobble them up
That is what I have been doing for years. If they are not completely dry, I lay them out on the windowsill for a few days and then crush them. My girls love the crushed shells andI have never had a problem with egg eating!!
 
That is what I have been doing for years. If they are not completely dry, I lay them out on the windowsill for a few days and then crush them. My girls love the crushed shells and I have never had a problem with egg eating!!
I never rinse.. water is a precious resource here in California.. just set out to dry before adding into my "crushing" jar, lid OFF.. noting that it needs to stay large particles and NOT fine dust in order to stay in the gizzard long enough to be better absorbed/utilized by the chicken. Rinsing doesn't kill any bacteria or spores. If I need to rinse egg shells.. I just compost them.. as all gardens *seem* to need calcium (in MY experience), then finer crushing may be helpful. Heating in ANY manner is also a waste of my time AND other resources, though it MAY be a good option for some.. it doesn't magically change it and I've even taken out whole boiled eggs and simply stepping to crush or simply throwing down hard to break wide open (accidentally cracked) raw egg out in the yard (not the lay box of course). Chickens are brilliant.

Never had an egg eater caused by this.. any egg eating here has been a happy accident from a brittle/soft new layer hiccup and never became habitual. 1 fake egg is kept in each box here to HELP detour curiosity pecks of newly maturing layers. The article covered lot's of bases pretty well though including what some folks have faced.

Friends, calcium can also be found in LOTS of plant sources also.. and it has NOT been stated (that I saw).. lack of such can lead to egg binding and even death! Sometimes other nutrients may need to bond with one another to be utilized and if one is missing the other is not going to help. Balance is always key. Re: gardening.. calcium is water soluble and cannot be absorbed while dry.. so it may be MY watering skill that causes deficiency seen in MY garden.. yet another reason WHY hydration is also ALWAYS key.

FINAL NOTE.. gout and kidney failure OFTEN have to do with GENETICS in addition to incorrect feeding and should NOT be solely pointed at or fear mongered about calcium alone.. EVEN folks with NO intention to fear monger but only hope to share knowledge will have SOME who grab onto and run with bits and pieces. It's ALWAYS important to do your OWN research and follow up on things that are stated and choose what makes the MOST sense according to YOUR perspective and goals..

Salmonella is killed at 165 degrees. That is why they recommend you cook chicken to 165 degree internal temp.
Pleas also understand that Salmonella cannot be caught by humans if your flock is NOT carrying it.. that's WHY we do not feed shells from outside sources AND buy only NPIP certified chicks/birds. Salmonella egg recalls is THE reason I started keeping my own chickens! You'd be SHOCKED at how long a fresh harvest chicken stays smelling normal and not slimy when done so at home without all the cross contamination that happens in commercial settings!


I agree don’t put in fridge to much of a moist environment.
You may be misinformed about modern refrigeration.. which has a condenser to remove humidity/moisture from the environment same as air "conditioning".. AND in fact dries things out.. Freezing will preserve some moisture before drying. If you wish to preserve bread with maximum freshness.. freeze, do not refrigerate... is my current understanding anyways. :confused:

The cold temperatures >40 degrees WILL delay and slow the reproduction of mold and bacteria verses room temperature.. and personal ambient humidity MAY be a factor.. we run at LEAST 65% humidity indoors most the year round at my CURRENT location. Previously it was only about 15%.. You are correct though that humidity DOES increase growth of undesirable stuff and avoiding it during storage of the eggs shells is a wise decision. :thumbsup

Sorry so long.. ya'll are so good to me.. I'm excited to be back after a short break!
 

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