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Eggshells as a Calcium Supplement for Chickens

The other day, a visiting friend noticed a cookie sheet filled with baked eggshells cooling my counter and inquired about it.  I guess it does seem a bit odd to have eggshells sitting out on the counter.  I can certainly appreciate the novelty of it as it's not something seen in every home.  Prior to starting our own flock a few years ago, I'd never heard about chickens eating their own eggshells, either.

Eggshells are a good way to supplement calcium in a chicken's diet.  Chickens need extra calcium in order to maintain their health and for hens to produce a thick protective shells on their eggs.  In fact, one of the signs that hens need more calcium in their diet is if their eggs become thin shelled.  This has happened with our own hens a time or two when I haven't put an extra form of calcium out for them.  At times we have provided them with crushed oyster shell, which is also an excellent calcium supplement.  However, purchasing oyster shell increases the costs of raising hens and is really unnecessary when we could be using their own eggshells instead.

To prepare eggshells for the hens' consumption, the eggs should be washed first to remove any bacteria.  We always wash the eggs before we use them for cooking with anyway, and so this step is already done ahead of time.  Whenever we use our hens' eggs, we then put the empty shells into a bowl in the refrigerator. After a few days or a week, when enough eggshells have accumulated in the bowl to make it worthwhile to give to the hens, we then take the bowl out of the fridge in order to bake the shells.

For easier cleanup, I line a cookie sheet with parchment paper before placing the eggshells in a single layer across the sheet.  The eggshells are then baked in a 220 degree preheated oven for about 20-30 minutes. Any egg white that remains inside the shells will turn a yellowish brown, which is an indicator that the eggshells are thoroughly cooked.

Once the shells have cooled, they can then be crushed into small pieces.  Nothing special is needed to crush the shells; I just use my hands and press on the shells until they are crumbled into small enough pieces.  The shells must be crushed in order to help deter chickens from eating their own whole fresh eggs (which they will do if you start down the path of giving them whole eggs).

The crushed eggshells are now ready to be fed to the chickens.  We simply sprinkle the shells onto the ground in a little pile and the chickens will pick through the little bits of shells and help themselves to as much as they need.