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Calcium supplements for chickens can help you avoid shell quality issues in your flock, and it’s easy to feed. Farmers have been adding calcium to the diet of layers for generations to improve shell quality, and consequently, we’ve learned a few things about it.
Why Add Calcium?
Calcium is an essential nutrient in the diet of poultry. Not only do chickens need to build and support healthy bones, but they also need enough free calcium in their diet to produce a hard eggshell.
Shell Flaws
Not all shells are created equal. An ideal shell is relatively smooth, evenly colored, and maintains a consistent shell thickness. Sometimes you get bumps and deposits on your shells, which is no big deal. If, however, you see dark spots that crack easier than the rest of the shell, you have thin spots. Additionally, if your eggs are breaking too easily, you may be experiencing thin shells.
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Soft Eggs
When the shell gland fails to produce a shell, a hen can lay an egg that appears to have a soft shell. If you’ve ever asked why is my chicken laying soft eggs, then you’ve seen this anomaly before.
“Soft-shelled” eggs are a bit of a misnomer. These eggs don’t have a shell that’s soft, but instead, they don’t have a shell at all. These eggs only have a shell membrane on the outside. The membrane usually holds the whole mess together, but it’ll feel like a wiggly ball of fluid.
Causes of Shell-less Eggs
Shell-less eggs are not usually caused by calcium deficiencies. Stress, illness, or lack of proper nutrition are more likely to be the reason your hen lays an occasional “soft-shelled” egg. Shell-less eggs do become more common as a hen ages, so don’t be surprised if you find one now and again.
When Not to Add Calcium
Young birds should never eat high calcium diets. Having more calcium than they can adequately absorb causes damage to their kidneys and therefore can shorten their lifespan.
It’s okay to feed grit for chickens to young birds, but don’t feed them oyster shell. Many people incorrectly think these two products should always be supplied together, so don’t make that assumption.
When to Add Calcium
If your birds are otherwise healthy, but you start seeing shell quality issues, it’s time to add calcium supplements for chickens to your feeding program. Routinely finding sub-par eggs in a healthy flock, such as thin shells, thin spots, and general malformations are all signs of poor shell quality. However, lumps, bumps, and extra calcium deposits on eggshells won’t be solved by adding calcium to a hen’s diet.
Molting chickens, or birds that have already molted at least once, are old enough to have free-choice calcium supplements for chickens. If you have shell quality issues in birds that have not experienced their first molt, look elsewhere for your problems.
Don’t Overlook Problems
Shell quality issues in first-year layers are usually because of management issues, so don’t assume that adding calcium will fix it. Some common issues that’ll result in reduced shell quality in first-year layers are changing over from chick feed too late, poor choice of feed, stress, and crowding. If you’re getting weak eggshells, make sure you’re feeding the right stuff and make sure all your bird’s needs are met.

Diseases and Egg Shells
Infectious Bronchitis and other chicken diseases are also known to cause shell anomalies. Talk to your local or state veterinarian if you see odd shells consistently from your flock, and ask their opinion on the matter. Otherwise healthy looking flocks that routinely lay malformed eggs may have a low-level infection. Usually, blood or fecal tests will tell the vet what they need to know.
Calcium Supplements for Chickens
Crushed oyster shells are an excellent source of calcium, and are the most common way flock owners supplement calcium in their flock. Some people also clean and crush their used egg shells and feed them back to their hens. This works perfectly well, even though it may be a bit time-consuming.
If you believe it’s time to add calcium supplements for chickens to your flock’s diet, it’s an easy thing to do. I don’t suggest adding it directly to their regular grain because no one ever mixes it to their chicken’s liking. Birds will pick out and toss your oyster shell while looking for more grain, wasting your supplements.
Free Choice Oysters
Chickens are quite good at regulating themselves and know when they need a little more calcium in their diet. I suggest placing a dedicated feeder in your coop or outside run full of crushed oyster shell. When your hens need it, they’ll eat some. Just be sure the feeder is protected from rain because wet oyster shells will clump up.
Many people mix chicken grit to the mix, which is excellent if your birds don’t go outside. If your birds roam the great outdoors, don’t waste your time and money on grit, because they’re picking it up as they forage anyway.
Do you feed your birds calcium supplements for chickens? How do you feed it? Let us know in the comments below and join the conversation!