What causes soft-shelled eggs?

Answer:

They may be the result of diseased organs of reproduction and especially of the oviduct.

Excessively fat hens are liable to lay soft-shelled eggs when the layers of fat are so abundant as to force the egg out before it can receive a sufficient coating of shell.

Heavy laying birds are also thus afflicted, by reason of the egg passages being weakened by continual strain and not being able to retain an egg after the shell begins to harden.

In exceptional cases it may be the lack of shell forming elements in the food.

Sometimes a chicken will lay very soft eggs at the start of her laying cycle.  You might possibly get no shell at all, or you may get some double yoked eggs.

Usually it may take a little time for your hens to adjust to the process of laying. Rest assured, they do catch on and work it out.

Egg shells are made mostly of calcium carbonate. A young pullet's need for calcium is low. But, when reaching maturity, her calcium requirements can quadruple to produce egg shells.

If you are having a problem with soft shells on a regular basis from hens that have been laying for awhile, your first course of action would be to add additional calcium to her diet. Addition of calcium may take up to four days for results to appear.

If soft shells or misshapen ones are a regular problem in mature hens and additional calcium has not rectified the problem, consult a veterinarian.

There are a few diseases and infections that could be present, like the ones listed above, and need to be addressed. In this case there would most likely be other symptoms present.