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

if you have too many shells, smash em up and put them in the dirt or composter, the plants will love it, worms may munch on them too even. Cant get salmonella if you don't keep them laying around. you should be getting fresh shells about every day or so right?

Aaron
 
If it's in their eggs already then they already have it, and if one of them got it, as close as they are, they all got it. Mold and other stuff that could cause other issues, would help it to be eliminated by not keeping the shells around. If you did keep them for a time, id think, do something to help dry them out, roast them or something, gooey egg shells would be a horrible incubator of heebies Id think.

I may be wrong but think that just using the fresh ones would be less prone to something bad growing.

Aaron
 
If it's in their eggs already then they already have it, and if one of them got it, as close as they are, they all got it. Mold and other stuff that could cause other issues, would help it to be eliminated by not keeping the shells around. If you did keep them for a time, id think, do something to help dry them out, roast them or something, gooey egg shells would be a horrible incubator of heebies Id think.

I may be wrong but think that just using the fresh ones would be less prone to something bad growing.

Aaron
Drying or roasting has already been suggested multiple times.
 
Why? There are always new eggshells. :idunno. I rather use my freezer for food and scatter the eggshells it in the garden if I have too much for the chickens. Especially the grapes love it if they get an extra egg shell boost.
I just like to prepare them on Saturday morning for the girls if we make angel food cake that 13 to 14 she’ll at once they don’t need that much at once. I have plenty of freezer space in the deep freeze. The egg shells sit by the tequila!😂
 
You know, if you REALLY just HAVE to have those egg shells, I can't argue with you, but those Angel Food cakes are awfully big and fluffy, and take up a HORRIBLE amount of room that you could be using to store those egg shells in. I would be more than happy to take a few of those huge cakes off your hands if you need the room :)

Aaron
 
I follow the same practices mentioned, and toast the egg shells in the oven. It makes them really easy to crush by hand into small pieces, and my chickens love this much more than the oyster shell I've tried.
I live in the Virgin Islands, and surprisingly none of the feed stores stock oyster shell--everyone just seems to rely on the calcium in the layer feed. Shipping bags of oyster shell here is pretty expensive, especially if they're not fond of it. I've been experimenting with collecting sea urchin 'tests' on the beach--those are the sun-bleached skeletons of pure calcium carbonate. They're super brittle already, and a short bake in the oven sterilizes them and makes it even easier to crumble. The chickens loved that! Exploring some other brittle calcium carbonate options from sea creatures and calcium carbonate-containing algae like Halimeda.
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I follow the same practices mentioned, and toast the egg shells in the oven. It makes them really easy to crush by hand into small pieces, and my chickens love this much more than the oyster shell I've tried.
I live in the Virgin Islands, and surprisingly none of the feed stores stock oyster shell--everyone just seems to rely on the calcium in the layer feed. Shipping bags of oyster shell here is pretty expensive, especially if they're not fond of it. I've been experimenting with collecting sea urchin 'tests' on the beach--those are the sun-bleached skeletons of pure calcium carbonate. They're super brittle already, and a short bake in the oven sterilizes them and makes it even easier to crumble. The chickens loved that! Exploring some other brittle calcium carbonate options from sea creatures and calcium carbonate-containing algae like Halimeda.
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That's super cool that you can find your own calcium sources from the wild!
 
[QUOTE="K0k0shka, ams-comment: 517052, member: 546781" 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.[/QUOTE]

I am definitely going to give this a try. One of my hens lays eggs with thin, thiiiin shells and lumpy calcium deposits. She seems to not care for the oyster shells all that much, as I've provided it but not seen much of a change in her eggs. She sees the others eat it and tried a peck or two, but she prefers to go for the chicken feed and scratch for bugs.
However, today I have seen her just vacuum up the crushed eggshells I tossed in the compost pile. I will see if giving her more will help.
 
I play it safe and only use the shells from hard boiled eggs (about 1/3 of my eggs). No need to do any additional baking. Just peel the egg, leave the shell for a day to dry off and then crush. Between those shells and the layer feed, I've almost never touched the bag of oyster shell that I bought.
 
So glad you mentioned the eventual diminishing returns in the amount of calcium in egg shells. Some folks aren't aware of this, and wonder why their eggs have problems when their hens' only source of calcium is egg shells. Great article!
 
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.
That is exactly what I do no rinse, toss in metal container on the counter and pop I oven whenever it is cooling down after I cook something
I will add that cooking them makes them easier to crush into little pieces.
 
I thought I would share what I do as it is pretty easy.

When I cook with my eggs, I wash the outside of the eggs, crack them open, put the egg in whatever I am using them for, then rinse out the inside of the eggshell while the tap is still running and then spread the eggshells out on the toaster oven baking sheet. Once they dry out, or when I get around to it, I put it in the toaster oven on a dark toast setting. Then when cool I crush them a bit in my hands and keep them in a Tupperware on the counter. I offer both crushed eggshells and oyster shells on the side for my chickens. They love the eggshells and eat that first. I have had no issues with them eating their own eggs.
 
I made an oyster shell feeder from 2" pvc piping with a 45 on the bottom. The eggshells go in there with the O S. Figuring that way they will not confuse them with fresh eggs. A little O S, a little egg shell each day.
 
  • I wouldn't feed your chickens eggshells from store eggs. These often have chemicals sprayed on them.
Oooh! I didn’t think about this. :-( I have been treating these the same as their shells. I rinse a bit under water then leave in extra egg carton by the sink until I have enough to dry in toaster oven at 170F for its max time which is 4 hours. Guess I will toss the store bought shells from now on. Thanks!!
I buy organic eggs and if i feed them to chicken including shells, i hard boil the egg and divide it for the 6.
 

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