Soft Shell and Rubber Eggs- New Layers

[Lizandherchickies]

Hello,
I have 4 RIR and 3 Golden Comet that are 21 weeks old.
They began laying eggs July 4th (yay). They are on pellet Nutrena Nature Wise Layer Feed and have access to a bowl of oysters shells. However, I still find 1 to 2 soft/rubber eggs a day. Usually broken from either falling from the roost at night or the girls breaking it apart to eat the yolk.

Is this normal at this age to still have soft shells this often? I had a chicken a few days ago witha soft shell membrane hanging from her vent & I had to slowly pull it out so I want to further prevent any health issues if possible. Any advice?

 

[aart]

Guessing the soft eggs are from other birds coming into lay,
they don't all start on the same day
It can take up to a month or so for thing to smooth out.
Are they eating well?
Partaking of the oyster shell?
Is it hot where you are?