Wait. Why exactly am I feeding eggshells to chickens? I’m glad you asked!
Eggshells are made of mostly calcium carbonate. Chickens need lots of calcium so that their eggshells are thick and unbreakable (well, not totally unbreakable, but you get the idea).
If a chicken doesn’t get enough calcium she may not lay as many eggs or her eggshells may become so weak that they get stuck in the oviduct (called egg-binding), which, like crop issues, can be a serious, and life threatening issue.
Chicken feed should provide enough calcium for any hen but just like us humans, each chicken is different and has different dietary needs. Offering supplemental calcium will allow the ladies who need more calcium to get it.
Oyster shells are another option for supplemental calcium but I prefer not to buy something when I already have a perfect supplement on hand.
Feeding eggshells to chickens
There are many ways to do it and every chicken farmer does it differently. Here’s how I feed eggshells to chickens (an even simpler system below).
I keep a jar for eggshells on my counter. When I use an egg I rinse the egg shell and let it dry on the counter for a while before putting it in the jar. If I put wet or eggy shells in the jar, the shells start to smell terrible(!) and they never dry out.
When the jar is full, I dump the eggshells out onto a large baking sheet. I bake it in the oven at 300 degrees for 10 minutes.
When they come out I either throw them into the blender and pulse a few times or I just use my mortar and pestle. As long as they are dry you can also just hand crush them (which I do often).
I then throw a little crushed eggshell in when I bring scraps out to the chickens. Some people recommend offering it in a separate dish so they don’t eat too much eggshell but I just throw everything on the ground for them to scratch and peck through. They love it!
I also believe that chickens can instinctively get what their bodies need as long as it’s available. (I mean, they did thrive for many years before domestication, right?)
Note: eggshells shouldn’t be fed to baby chicks. Only laying age hens (6 months+ old) need calcium.
Why do I crush the eggshells?
Crushing them makes them unrecognizable as eggshells. Some hens will start breaking and eating her eggs after being fed eggshells, most won’t, but this helps ease my mind.
Update: I’ve gotten lazy with the crushing part but my girls still don’t eat their own eggs (unless I drop one and then they run over to check it out). I don’t worry about crushing anymore.
Need something simpler?
If you want to really simplify things, you could take uncooked shells out with scraps each day instead. Cooking the eggshells just makes them easier to crush, so if you don’t want to crush them then you really don’t need to bake them. Honestly, I just let the eggshells dry on their own then crush them a bit. It works great and takes way less time!