Rubber Shelled Eggs

[kzims]

I have a buff laced polish hen, she is around 18 month old and has been an extremely good layer. For the past 2 months we have had a severe heat wave with temperatures ranging between 99 to 105 degree Fahrenheit. During this most of my other polish hens stopped laying, so did this one.
However I have given them fan and extra shade and most of my other hens have started laying once again. This buff polish hen however has been laying soft/rubber shelled eggs for past two weeks. During that she also laid 3 to 4 hard shelled eggs as well but all other eggs had rubber type shells.
I have been giving her calcium supplements and crushed egg shelled mixed in her feed in addition to other minerals and nutrients regularly but after every alternate day she keeps on laying eggs that are rubber shelled.
I need an advise on how to get rid of this problem. The hen is otherwise very active and looks normal.

 

[Eggcessive]

Make sure she is taking the calcium, and give her a little vitamin D or D3. I have 2 chickens that no matter what they take, they have a thin shelled egg. She could have trouble processing the calcium.