In order to produce hard eggs, chicken need to consume 20 times the amount of calcium than is contained in her bones. With this in mind, it is important to provide the appropriate amount of calcium steadily into the diet.
Many chicken owners crush eggshells and feed them back to their flock. While this is a great way to recycle, it may also present some risks, the greatest being salmonella. Salmonella can be found on the inside and outside of eggs. Feeding your hens eggshells infected with this bacterium can cause this sometimes fatal illness. The only way to be sure to prevent this is to bake the eggshells, which can be time consuming and impractical. If a hen becomes infected with salmonella, it affects the eggs and increases the risk of humans getting the bacteria from the eggs.
The Best Calcium Supplement Options
Feeding oyster shells or limestone is the best option for supplementing calcium. Though this may seem like a higher investment up front, feeding your laying chickens oyster shells or limestone instead of their own eggshells with pay off in the end. The good news is that a little bit of these products go a long way – a 50 lb. bag of oyster shell or limestone will last the average flock for up to several months for a flock of 6 – 8 birds. Feeding these products is easy – simply put the oyster shell or limestone in a separate container and allow birds access free choice. Your girls will take what they need.
Just keep in mind that when it comes to calcium supplementation for your flock, ground limestone or oyster shells are safer options than feeding eggshells back to your girls.
Source: Nutrena/The Scoop From The Coop