Hen stealing all the calcium!

[chunandsnuggles]

I have two hens, one of them always has calcium deposits on her eggs, and the other one usually has normal eggs. Yesterday, the normal layer layed an egg with no shell! And she's been laying less frequently in general.
Is the first one somehow taking all the calcium? How can I fix this?

 

[ChickenCanoe]

How could that be? How could a hen extract and steal the calcium component in feed? Do you feed a complete layer feed?

 

[chunandsnuggles]

How could that be? Don't you feed a complete layer feed?

Yes, it comes with oyster shells but I'm guessing maybe the first one eats them all before the other can?

 

[ChickenCanoe]

The oyster shells are separate from the feed?

 

[chunandsnuggles]

The oyster shells are separate from the feed?

No they're mixed in