The modern laying hen has been bred to produce a staggering amount of eggs each year. The White Leghorn and Golden Buff are particularly adept at laying approximately 300 eggs per year as long as they are managed appropriately. But what does “managed appropriately” mean exactly? In this post, we’ll discuss the role of dietary calcium for laying hens, in the management of your flock.

Not Enough Calcium? Or Is It Too Much?

Feeding table scraps and allowing chickens to free range may cause a nutritional imbalance which may lead to weak or missing eggshells. The ratio of calcium to phosphorus is particularly important. When most chicken owners discover eggs with weak shells, they assume there is a lack of calcium and begin to supplement with oyster shell or crushed limestone. While it may be true that weak shells equals calcium deficiency, it could also mean a phosphorous deficiency. Supplementing calcium when phosphorus is deficient actually makes the weak eggshell problem worse. 

Offering both calcium and phosphorus free choice and NOT mixing either into the layer feed will allow hens to supplement their diet with either mineral as needed. For most chicken owners, it’s easier to feed a layer ration and not bother with supplementing calcium or phosphorus. If you do decide to supplement your flock with calcium, it may also be a good idea to supplement with phosphorus also. The easiest way to do this is to offer defluorinated rock phosphate in a separate dispenser next to the oyster shell calcium. But nearly every commercially prepared layer feed will have adequate calcium and phosphorus levels.

Who Doesn’t Need Calcium

Feeding layer feed to chicks or pullets before they begin to lay eggs may permanently set them up for trouble. Excess calcium in a non-laying chicken’s diet can lead to kidney damage. The damage is irreversible and may result in a decrease in potential laying ability for the hen’s entire life, or even death from kidney failure over time. 

The same is true for a rooster, he doesn’t need calcium. Over time, roosters that eat layer feed will probably develop some degree of kidney damage. But if you’re like me, it would be impossible to feed your rooster one feed and the laying hens something else, so my roosters get the layer feed also.

When Eggshells Have Issues

Eggshells that are thin, missing, or have a rough, pimply surface could indicate several things. It could mean a lack of either calcium or phosphorus, or any of the other trace minerals. As previously mentioned, try offering both calcium and phosphorus free choice and see if the issue resolves itself. There are some diseases, such as Infectious Bronchitis that can cause scarring of the oviduct and shell gland, which could cause the same eggshell issues. If supplementing doesn’t correct the issue and you can recall a time when your flock was sick with an upper respiratory illness, suspect IB. In this case, the damage is irreversible and you are left to deal with weak eggshells.

Have you dealt with weak eggshells? Let us know in the comments how to correct it. Or if you were not able to correct it, what did you do about it?