Have you ever wondered if feeding eggshells to chickens as a calcium supplement is ok? Short answer: Yes. Yes it is!

Do you need a calcium supplement?
Only you can answer this. I like to let my hens get a layin’ and then see how their shells are turning out. If they are a bit softer than I’d like, I supplement. This depends almost completely on what you are feeding your ladies. I always recommend feeding a professionally balanced feed available free choice at all times in addition to whatever else you’d like to feed. The professionally balanced feed will have a high Ca content and depending on how much of it your hens eat, they may not need anything else. For example: in the summer, my hens graze a lot so they need more Ca supplementation than they do in the winter when they are primarily eating the balanced feed. Now, I hear tell that people own chickens that have free-choice to Ca supplement and they only eat it when they need it. While this may be true in some cases, it isn’t always going to be true and if you find yourself with eggshells hard as granite, take it away! Your hens obviously don’t need it. If you aren’t feeding a professionally balanced diet, leave a Ca supplement you purchase from a feed store out at all times. Not having a diet professionally balanced can create many problems, especially with egg laying. Soft shells can cause eggs to get hung up inside your hen, which is a major problem. I always prefer a professionally balanced diet when I am using my animals for food production, it is my responsibility to give them the nutrients they need to produce food for me. I do not have access on a small scale to all the feeds they require to have a balanced diet, and you probably don’t either. Balanced livestock diets are SO important – don’t mess around!Feeding eggshells as a calcium supplement
You can purchase Ca supplements in the feed store, usually in the form of oyster shell. Oyster shell is a good supplement because it is 95% calcium carbonate, and your hens eggs are also 95% calcium carbonate. Why the carbonate part? Well it has to move through your hens digestive tract and then through the blood to be taken to the uterus where the eggshell is formed. Calcium can’t do that all by it’s lonesome because it’s a positively charged ion. But that is another lesson for another day. Suffice it to say that it needs a traveling buddy to make it all the way there. So. When that guy on the “Chicken Lovers Unite Facebook Group” your a part of says that feeding eggshells back to your hens is bad because it’s hard for them to access the Ca in them, what should you say? Politely tell him he is full of chicken sh*z. Because eggshells and the most popular calcium supplement for chickens {oyster shells} have an almost IDENTICAL chemical makeup.Yes. I just said chemical. And it’s ok. Because life is full of them. And we are all made of them. And so is water. Amen.Anyways. My points are as follows:
- Please trust professionals. Not just anyone with an opinion.
- You most certainly can feed eggshells back to your chickens as a supplement.
Kathy Shea Mormino, The Chicken Chick says
Hi Alli,
It’s important to note that eggsells are not a sufficient source of dietary calcium alone. A laying hen would need to consume approximately 2-3 whole eggs’ shells daily in order to get their RDA of calcium and…size matters- bigger particles in the form of oyster shell, for example, are better than small/thin sources such as eggshells. In multiple studies, it was found that hens sought out large particles of oyster shell late in the day, prior to the most rapid period of shell formation overnight, in order to supply themselves with a continuous supply of calcium when it is most needed. http://www.the-chicken-chick.com/2013/08/for-strong-eggshells-size-matters.html
Yours in Poultry,
Kathy Shea Mormino
The Chicken Chick®
Alli says
Hi Kathy, Thanks for your comment. I appreciate you pointing out the eggshell quantity does matter, you are most certainly correct. In much of the cited literature, the most important thing to be concerned about is feeding your hens a professionally balanced layer feed at free choice, much of the calcium they need will be supplied there. That is why I was very clean in the beginning of the post to point out that you should always supply a purchased source of calcium for your hens if you are not feeding a balanced layer feed. Additionally I pointed out that if your hens eggshells are a little thin, supplementation other than eggshells will also be necessary to prevent problems. It’s also important to note that even with oyster shell supplementation or other forms of supplemental calcium, hens will still draw calcium from their body supplies. (Basics of Animal Nutrition and Feeding (Chapter 26), 5th edition, Pond et al., 2005). Thanks again for stopping by!