Using Eggshells as a Calcium Source

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This article is in the series Natural and Healthy Chicken Keeping
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.
IMG_20200802_095756.jpg
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
I keep chickens, pigeons, cats, bees, and a rabbit!

I love nature and am working on becoming more self sufficient. I also 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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Very good article. I like it to reuse things if possible and egg shells are even better (easier to digest ) then the OS.

I read some informative comments too, some with good extra info like: don’t wash the shells , the egg-white in the shells are very nutritious. To keep it safe I put the egg shells in the microwave for a few seconds and give it back the next day. If there is more then they will eat it goes into the soil of the run. Together with leaves, weeds, grasses and poop it wil break down into a great and fertile topsoil.

There is one thing that needs a bit more explanation. The layer feed with calcium should not be given to chicks because of kidney damage. But there is no evidence that roosters and not laying hens get kidney problems from layer feed if I can believe what I have been reading (experiences from other BYC members). Nevertheless I am cautious and I prefer to feed my hens all flock in winter. Especially because I have 4 oldies now who don’t lay much eggs anymore.

If I buy extra eggs in winter I choose the organic eggs. These shells are not poisoned and are safe to feed to the chickens as well.
Great article explaining the different ways!
I did alot of research about this topic and there are so many different opinions. I opted for the air dry and the girls LOVE them. They eat the shells much more than the oyster shells!

Thanks for sharing!

Comments

  • 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!!
 
This is great - all of the best information in one place! Very helpful, easy to understand, and clears up some common mysteries regarding eggshell consumption and calcium intake.
I may have just bought my last bag of oyster shells! 👍
 
I have always been afraid to feed my hens egg shells, because i thought it might encourage eating their own eggs, so i would buy oyster shells, but i would like to give the different methods a try after reading this!
 
I had saved egg shells for a year before I had chickens & crunched them up after rinse , air dry . Kept in an igloo cooler . Just started giving them to the girls as they just started laying ....hoping not to have to buy oyster shell ever :) Most of the shells are from fresh egg seller in town , maybe a handful from store bought eggs ...... washed,aged & baked should be ok ?
Great article !!!
 
I had saved egg shells for a year before I had chickens & crunched them up after rinse , air dry . Kept in an igloo cooler . Just started giving them to the girls as they just started laying ....hoping not to have to buy oyster shell ever :) Most of the shells are from fresh egg seller in town , maybe a handful from store bought eggs ...... washed,aged & baked should be ok ?
Great article !!!
I think they'll be fine! And a few store bought shells mixed in can't do much. Have fun
 
I think they'll be fine! And a few store bought shells mixed in can't do much. Have fun
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
 
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
Mine are in a open-lid container in the cupboard or on the counter. Funny, I've never had any mold. I guess to play it safe you just have throw those away and start collecting again. :confused: I would be interested to hear if this happens again!
 
Mine are in a open-lid container in the cupboard or on the counter. Funny, I've never had any mold. I guess to play it safe you just have throw those away and start collecting again. :confused: I would be interested to hear if this happens again!
This was many months ago. I trashed those and haven't tried since. I am anxious to try again though and this article has certainly got me excited to try again. Maybe I should start rinsing the spent shells before storing
 
I have heard from a few sources that this is not a good thing because you can give your chickens Salmonella from the egg shells. I honestly don't know but do know they eat some pretty horrific stuff sometimes!! so not sure on the Salmonella part.

Anything we can do to recycle and save a buck for the 'bucks' they give us is always a good thing.

Good article, thank you
Aaron
 
I have heard from a few sources that this is not a good thing because you can give your chickens Salmonella from the egg shells. I honestly don't know but do know they eat some pretty horrific stuff sometimes!! so not sure on the Salmonella part.

Anything we can do to recycle and save a buck for the 'bucks' they give us is always a good thing.

Good article, thank you
Aaron
Maybe if you're feeding them shells that aren't their own? I'm curious now because the birds that laid the eggs would need to be carrying salmonella, right? @Eggcessive. @dawg53 please see the above post
 
Maybe if you're feeding them shells that aren't their own? I'm curious now because the birds that laid the eggs would need to be carrying salmonella, right?
That's what I was thinking myself, however if one of your hens had it and you crushed her eggs and gave it to the rest of your flock, they could get it? Or couldn't they get it just being with her too? Many animals naturally have it to begin with so is it really a bad thing? For US yep it's not good but for them? I seen that on a PooTube video, where you know, everyone is an expert at everything, just ask them! so honestly don't know the validity of that statement. If you let your hens free range though, I can't see how they'd NOT catch it sooner or later just doing what they do!

Personally just using what tiny amount of common sense I sometimes borrow, Id think, as long as you grind them up so they can't tell they are eggs and get the idea to peck their eggs in the nest, it should not be a issue. Crack it, Smash it, Re Feed it the next day or so.

Aaron
 
I rinse the shells when I break them open for the egg inside. After that I microwave them and break them into relatively large chunks. Works great and it's my hens' favorite source of calcium.

A neighbor saves me shells too. I don't believe she does more than air dry them. I'm grateful for her shells but even after I microwave them they tend to stay in clumps.
 
I have heard from a few sources that this is not a good thing because you can give your chickens Salmonella from the egg shells. I honestly don't know but do know they eat some pretty horrific stuff sometimes!! so not sure on the Salmonella part.

Anything we can do to recycle and save a buck for the 'bucks' they give us is always a good thing.

Good article, thank you
Aaron
Maybe if you're feeding them shells that aren't their own? I'm curious now because the birds that laid the eggs would need to be carrying salmonella, right? @Eggcessive. @dawg53 please see the above post
That's what I was thinking myself, however if one of your hens had it and you crushed her eggs and gave it to the rest of your flock, they could get it? Or couldn't they get it just being with her too? Many animals naturally have it to begin with so is it really a bad thing? For US yep it's not good but for them? I seen that on a PooTube video, where you know, everyone is an expert at everything, just ask them! so honestly don't know the validity of that statement. If you let your hens free range though, I can't see how they'd NOT catch it sooner or later just doing what they do!

Personally just using what tiny amount of common sense I sometimes borrow, Id think, as long as you grind them up so they can't tell they are eggs and get the idea to peck their eggs in the nest, it should not be a issue. Crack it, Smash it, Re Feed it the next day or so.

Aaron
Salmonella, nobody knows much about it. I have never heard that feeding chickens their own shells gives them salmonella, but that doesn't mean it isn't true. One advanced chicken keeper I met said once that it was his belief that every person who has kept chickens for a couple years has or has had salmonella, and that most backyard flocks carry it but it doesn't bug them.
Anyways, I don't worry too much about it. I have a strong immune system, and so do my chickens. It won't hurt us.
 
I have raised Bearded Dragons, now Chickens, Have a Cockatoo who loves snuggles and kisses, and god only knows how many other pets over the years. A bit of Salmonella won't hurt me, im pretty sure ive been there many times in the past. Heck, just eating a McDonalds gut bomb will give you the squirts worse than any chicken kiss could ever do to you :D

aaron
 
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.
 

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