Quick Guide to Crushing Eggshells for Chickens

Eggshells.  We have them.  Anyone who eats eggs (not the pour-from-the-carton-type-of-egg) has them.  And if you eat eggs regularly, they can add up in a hurry.   And sure, there are sources that cite “10 Best Ways to Use Eggshells” or “Save those Shells for Projects”,  but have you ever seen the process on ‘how-to- crush’ the shells?

Now as we all have heard, eggshells contain calcium.  And for those of you new to keeping chickens, calcium is a must in a chicken’s diet in order to lay eggs with sufficiently hard shells.  (Some of you may have experienced a shell-less egg.  The egg itself is encased just in membrane.)  When chickens do not get enough calcium in their diet, they lay soft-shelled or shell-less eggs.

At the time my parents were raising chickens, the common rule of thumb was providing oyster shells as the primary calcium source to chickens.  But with sustainability on my mind, why pay for calcium product when I have something already on hand?  Eggshells can be ground and fed to chickens instead!  What a great resource for backyard chicken keepers.

Now grinding eggshells is a very simple process.  I keep a container on the counter where I deposit the eggshells.    The container is deep enough that it will easily hold at least one dozen eggshells (which is approximately the quantity of eggs we eat on a weekly basis).  The container is also deep enough that when I start the crushing process, bits of eggshells stay in the container rather than scattering beyond the container.

I do not wash them out, nor do I bake them. (Though if the shells have a lot of fecal matter on them, it is wiped off.)   I simply allow the shells…rather…. their membranes to dry prior to grinding/crushing the eggshells. Please note that you will want the membranes to be dry, otherwise the shell will be held together by the membrane when you crush it rather than crumbling into pieces.  In the picture to the left is a newly crushed eggshell with a membrane that has not dried.  The eggshell, while cracked, has held together in one piece.

Instead of using my hands to crush the eggs, I use my trusty muddler (regularly used for making mojitos).  It has surface much like a meat tenderizer tool, but with a smaller raised surface.  If you don’t have a muddler on hand, you can place the eggshells into a plastic bag and then crush them with the palm of your hand or you could run a rolling pin back and forth across the surface of the bag.

I crush the eggshells with an up and down motion.  The raised surface of the muddler ‘bites’ into the eggshells and readily breaks the shells apart with minimal effort.

The eggshells are crushed until they are fairly uniform in size and are quite small.  Note only do these small pieces easily mix into their chicken feed, but I hope that the pieces are small enough that the chickens do not perceive them as eggshells.

Another method for feeding crushed eggshells to your chickens is to simply put the crushed shells into a separate container that you keep within the chicken run.  But whichever method you choose, you can take pride in applying sustainability to your flock.

Crushed eggshells.  Simple.  Easy.  Sustainable.