If you own backyard egg laying hens, chances are you’ve paid good money to buy crushed oyster shells or some other kind of calcium supplement before.

If you own backyard egg laying hens, chances are you’ve also either composted or thrown away egg shells.

But what if I told you there was a way to reuse old egg shells are a calcium supplement, saving yourself both cash and trash?

You’re in luck. Because that’s exactly what I’m about to tell you.

[Sidenote - all of the incredible photos in this blog post were taken by my friend Oscar Avellaneda-Cruz, an amazingly talented photographer in Anchorage, Alaska. Photos: @okiave / Oscar Avellaneda-Cruz]

When a laying hen is in her prime laying age, she’s laying about one egg a day, on average.

While that’s great news for our breakfast plates, think about that from a resources perspective and what that chicken’s body must need to re-coop-erate. (Sorry for the pun – I couldn’t help myself.)

Why feed your laying hens a calcium supplement?

If you’re just feeding your backyard hens store bought chicken feed, most laying hen chicken feeds are pre-formulated to have the right amount of calcium their body needs to maintain laying strong, sturdy egg shells on a daily basis.

But if you’re like me, you might like to toss your backyard hens table scraps, occasional handfuls of grass while you’re weeding the garden, or let them free roam around the yard so they can gobble up bugs.

(Heck, I even free range with them like a dork – here’s video proof.)

While all of that is AMAZING for the quality of their eggs (their yolks always turn a more vibrant orange the days after free-roaming), it does change that perfect nutritional balance, making some sort of calcium supplement a necessity.

FACT – Egg shells are nearly pure calcium.

And when my chickens are laying well, egg shells are something I always have an abundance of. So why not recycle the egg shells as a calcium source?

Saving egg shells for the sole purpose of recycling them as a source of calcium is built into the way we live in our home. Setting aside shells is part of the route here.

There’s always a dish in the kitchen specifically for collecting egg shells. (You can also see my white, ceramic kitchen compost container.)

How to transform egg shells into a calcium supplement

I let the egg shells dry out for a few days, then I give them a quick toast in the oven just to make sure they’re crispy and dry.

Then I pull out the Ninja, a basic kitchen food processor. Any food processor or blender with a pump mode will work just as well.

I put all of the dried egg shells into the food processor and give it a few pumps – just enough so the shells are the consistency of very rough sand, but not a powder.

You want the size of the ground egg shells to be:

• fine enough so the hens can’t recognize that they’re eating their own eggs, yet
• big enough so the birds can still pick up pieces.

Once I reach that magic consistency, I pour the smashed egg shells into a big, glass jar for storage.

And that’s all there is to it.

Instead of buying crushed oyster shells, you can just feed your laying hens the crushed egg shells. Both shells – oyster and chicken egg – are essentially pure calcium.

Feeding laying hens the crushed egg shells (= calcium)

Whenever my backyard hens have had a day or two or free ranging the yard, or if I’ve given them table scraps, I’ll toss a handful or two or ground egg shells into their run area, too.

No need to force feed – they happily eat it up off the ground, then scratch around looking for more “treats.” They actually really enjoy picking up the tiny shells and eating them.

And as for storage, I just keep a glass jar full on my shelves, ready for feeding whenever my egg layers need a calcium boost.

I think it looks rather pretty, actually. Especially when your professional photographer friend comes over to document for you – thanks again Oscar Avellaneda-Cruz.

Sure, there will be times when you give eggs away and lose those beautiful, calcium-rich shells. There will always store-bought alternatives to supplement your flock’s calcium needs.

But if you have most of the calcium you need already right in your own home – and you know where it came from and how it was handled – why not use your egg shells for calcium?

Reuse, reduce & recycle. :)