Eggshells As A Source Of Calcium

In our “introduction to raising chickens” class my wife and I attended at the local extension school, the presenter discussed chickens’ need for calcium and that providing oyster shells is necessary.  One of the audience members asked about feeding the chickens’ eggshells back to them.  The presenter thought this was a bad idea, that oyster shells are pretty cheap and worried that feeding them shells could lead to egg eating behavior with your flock.  I’ve recently been feeding our eggshells to our vermicomposting worms and it got me thinking about and researching this again.

Why Do Chickens Need Calcium?

Chickens build the shells for the eggs they lay, in part, out of calcium.  They require calcium for bones and general bodily functions just like all other living creatures.  Their need of high levels of calcium makes “oyster shells” a commonly included product in chicken starter kits.

Signs of Calcium Deficiency

Thin eggshells, that will break while being collected are one sign that chickens aren’t getting enough calcium.  Misshapen eggs are another.  Sometime chickens eating their own eggs is a sign of a calcium deficiency.


The shells need to be crushed.  SOME people will try to sanitize the shells through heat.  This can be leaving them in a pan outside on a sunny day, heating them up in the oven or microwaving them.  Others just crush them and feed them directly to the chickens.

Part of the crushing is to get the shells into “bite sized” morsels.  Another purpose is to make them look less like eggs so chickens won’t be encouraged eat eggs.


some people, like in the video below, mix the crushed eggshells into the chicken feed.  This can cause problems if roosters are eating it, as they don’t have as great a need for calcium and eating too much can cause them problems.  Usually with calcium, either oyster shells or eggshells, it’s good to have a distinct dish for them that chickens can eat as much or as little as they want from.

Eggshells From Other Sources

It’s probably a good idea to only feed your own eggshells to the chickens.  If you’re getting eggshells from store bought eggs or from other crops, feeding them to your chickens would be a good way to introduce new bacteria and possibly diseases.

Egg Eating

The consensus, among people who have tried this and written about it, seems to be that providing crushed shells will not lead to chickens eating their own eggs.  To my mind, it’s certainly worth trying.  If your chickens *DO* start eating their own eggs, it would probably be a good idea to stop feeding them their eggshells.  The easiest cure for egg eating that I’ve heard about is to put golf balls into their bedding boxes.  The chickens will peck at them, not like the hard surface, then stop eating anything that looks like them (such as eggs).

Do you feed your chickens eggshells?  If you don’t, would you consider it in the future?