bag of oyster shells

Are Oyster Shells Really Necessary?

I am frugal.  Okay—cheap.  I never want to spend more than I absolutely have to.  When my hens first started laying, I purchased layer feed, knowing that layer chicken feed has calcium added to it, so my hens should be fine with just that.  Right?  Well, I started to notice thin and brittle eggshells after several months of my chickens laying.  Yes, it was probably my fault–I like to feed my chickens kitchen scraps and greens from my garden, so sue me! I read that I could supplement their diets with ground oyster shells for calcium.  OR I could grind up their eggshells and give that to them.  Hey—I already had eggshells, so that would be free!

The “Free” Option

As I read up on how to prepare eggshells for chickens, I learned about drying out the shells, baking them to remove any harmful bacteria, and then grinding them in a food processor or blender.  So I did that, and I threw the ground egg shells on the floor of their run.  They seemed to eat it, so problem solved.

Except that it wasn’t.

Hmm…I saved up more shells, baked them, ground them, and threw them out again.  And again.  But even though my hens were eating the ground-up shells, their own shells were still brittle.

Thin eggshell

I had to get over my extreme frugality and realize that if I wanted healthy chickens with nice hard shells, I would have to offer them a consistent form of calcium.  Did I want to be saving, drying, baking, and grinding their shells every few days?  Just cleaning out my food processor from the smell of ground eggshell answered that question.  Nope!

What I didn’t realize is that my hens needed the option of eating egg shells ALL THE TIME.  I was throwing out eggshells maybe every other week or so at best.

I finally decided that I needed to splurge and buy a bag of ground oyster shells.

picture of oyster shells
But What Size?

I was immediately perplexed when trying to shop for oyster shells.  There was a 50 lb. bag for around $14, or a 5 lb. bag for about $5.

Would a small flock of six chickens be able to eat 50 lbs?  Even 15 lbs?  Because saving money is a part of my DNA, I decided to go with the better deal and buy the big bag, but I had no idea if they’d ever even be able to put a dent into it.

oyster shell comparison
Do the Math
Chicken doing math


I was glad I bought the 50 lb bag, because they go through those oyster shells slowly but surely.  To be exact, my six hens eat 1.03 oz per day: that is .171 oz (4.8 grams) per bird.  So it would take them about two and a half months to get through the five pound bag.  At the same rate, it will take two years and one month for them to eat the entire 50 lb. bag.

Simple Feeder

Offering oyster shells is pretty simple.  I drilled a few holes in an empty canned chicken can and attached it to a 1″x 2″ x 12″ piece of wood. (I didn’t bother with drainage holes since my run is covered. ) I nailed a small sawtooth picture hanger up top so I could hang it on the wall of the run.

So far, so good.  If they eat the oyster shells, they need the oyster shells. No more brittle eggshells. Some things are worth a few extra dollars—this is one of them.