Feathered Friday: Crushed Egg Shells for Calcium Supplement

From the wee little anole skittering around in the bushes, to the two-hundred-pound English mastiff down the street, to your kids playing in your back yard. . . We all need calcium.  Chickens are no different.  And just like a pregnant woman, it's extra important for laying hens to have the appropriate amounts.  

A laying hen needs access to supplemental calcium.  The shells of her eggs are 94-97% calcium carbonate.  If she doesn't get enough in her diet, she will take it from her own body in order to make sure her eggs are strong.  (She will do this with other nutrients, too, but I'm focusing on calcium.)

Boo-boo pecking egg shells.

Now, you can go out and buy calcium supplements, usually in the form of crushed oyster shells.  (We certainly have more than our share here in the Chesapeake Watershed area.)  In fact, this is recommended even if you are giving egg shells.  I mix my egg shells in with the oyster shells.  

It's important to note that calcium supplements should always be offered free-choice.  This way the hens can take as much or as little as they need, when they need it.  Hypercalcemia--too much calcium--can be just as harmful as hypocalcemia--too little calcium.  Beyond that, calcium cannot be utilized by the body without vitamin D3, which can be produced by simple exposure to direct sunlight.  (It would be fascinating to go into the scientific details about calcium, V-D3, and hypo/hyper symptoms, but I'll save that for later.)

Here is how I prepare my egg shells to provide as a free-choice calcium supplement. . .

I do my best to crack the eggs so I get two nice halves I can get my fingers into.  All eggs have a membrane on the inside of the shell, and my experience has taught me it's easier to crush the shells if this membrane is removed.  

Membrane pull away from shell

I have tried rinsing, drying, and then soaking to remove the membrane.  It works, but it's much easier to do it while the membrane is still in its own gelatinous state.

Membrane stripped from shell.

I put the membranes in my compost pail, along with any tiny fragments of shell I can't get off.

Then I rinse the shells and sit them on a paper towel to dry.  

Larger pieces broken by hand

Once they are dry, I break them into large pieces by hand.  This is a preference thing, as the shells can be sharp.  But I like the sound and the feel of the breaking shells.  Like breaking glass, it gives a strange sense of release. . . but without the level of damage and mess.

To get the smaller pieces, you could use a zip-lock bag and rolling pin.  But here in Maryland, we have crab mallets.  Everything's more fun with a mallet, right?  Maybe, but I use the round part and roll it over the shells until they're the size I'm looking for.

This is the size I'm looking for.  It's good to have a variety in the pieces, with some larger and some powder in the container.

I put it in a bowl and the hens eat as they wish.


Happy egg crushing!