In order to actually make use of the calcium the birds need the proper level of vitamin D or get enough sunlight in order to produce it.
Older birds require more calcium than young birds.
The shell gland also can have its own issues.
Likewise a major disturbance can cause a hen to go off cycle and pass an egg without it having enough time in the egg gland.
While commercial layer feed may have enough calcium in it, you need to understand that feeding the birds anything other than that feed will reduce the calcium level they get.
The other thing that is implicated in the production of soft shell eggs is heat stress.
Older birds require more calcium than young birds.
The shell gland also can have its own issues.
Likewise a major disturbance can cause a hen to go off cycle and pass an egg without it having enough time in the egg gland.
While commercial layer feed may have enough calcium in it, you need to understand that feeding the birds anything other than that feed will reduce the calcium level they get.
The other thing that is implicated in the production of soft shell eggs is heat stress.