Wait. Why exactly would I feed my chickens eggshells? I’m glad you asked! Chickens need calcium for healthy bones (just like humans,) and to ensure that the shells on the eggs they are laying are thick and strong. If a hen doesn’t get enough calcium in her diet it can lead to the production of week-shelled eggs which can, in turn, cause them to become egg-bound. A condition where the egg gets stuck in the oviduct, which can be a serious, and life-threatening issue.
How Much Calcium Does a Laying Hen Need?
An adult laying hen needs between 4-5g of calcium per day. Here’s a fun fact, it takes a hen approximately 25 hours to produce an egg. Of that time 18-20 hours are used in shell production! During the 18-20 shell creation a hen can use and replace the calcium she needs in her bloodstream up to 100 times.
You can, of course, purchase calcium supplements at the feed store, usually in the form of crushed oyster shells which are 95% calcium carbonate. However, your hen's egg shells are 97% calcium bicarbonate, and they’re free, so I’ll let you do the math there…
Moving on, you may be wondering, why the bicarbonate part is important. Well, the calcium needed to create an eggshell must be provided by a hen's diet. From there it has to move through your hen's digestive tract and then through the blood to be taken to the uterus where the eggshell is formed. However, calcium alone won’t make it, it needs a “traveling buddy” in the form of bicarbonate.
A Few Cautions Before Feeding Eggshells
First up, never feed your chicken's egg shells from an outside source such as from a grocery store or neighbor's flock as there is some risk of spreading disease. The next caution is about
E. Coli. It is recommended that you heat your eggshells to kill any pathogenic bacteria that may be on them.
Thirdly, never feed eggshells or calcium supplements to baby chicks or pullets. Only laying hens above 18 weeks old need supplemental calcium. Excess calcium may reduce growth efficiency in baby chicks.
Lastly, the common sense caution. Don’t feed your chickens eggshells back to them as a supplement if they aren’t strong shells, to begin with. If your flock has less than sturdy shells, you should start with a purchased supplement until your ladies begin laying sturdy shells.
How to Feed Eggshells to Your Chickens
The preparation is simple and can be managed in just a few basic steps.
First clean and dry your eggshells. We wash our shells and set them on a plate to dry. Once dry they get transferred to a large container for storage until we have enough to move on to the next step.
Once you’ve gathered a significant quantity of shells, preheat your oven to 350 °F (177 °C).
Spread the shells evenly in a single layer on a baking sheet and bake for 10-12 minutes.
Allow the shells to cool completely. Once cool you can crush them by hand, with a mortar and pestle, or in a food processor. Whichever you prefer.
Why do I Need to Crush the Eggshells?
The primary reason for this is to make them unrecognizable as eggshells. The last thing you want to do is encourage your chickens to start “sampling the merchandise” and eating their own eggs before you can collect them.
Shells or No Shells?
It’s funny how many things there are in the chicken-keeping world to debate upon. Coop heat vs. no coop heat. Deep litter vs. base litter. Eggshells vs. oyster shells. At the end of the day, if you are feeding your flock a balanced layer feed the need for additional calcium may or may not be there, and too much calcium can be harmful to your bird's kidneys if they have to filter out excess calcium. As with any other treat or supplement, use sparingly. We by no means feed every single shell back to our flock but instead offer them on a by-choice basis so that birds who may need extra calcium can access it if they need it. Have you ever tried feeding eggshells to chickens? How did you do it? Tell us all about it in the comments below! And as always, until next time,