How long does laying "practice" eggs last?

[2DogsFarm]

OK - I think the 2nd of my pullets has started laying.
#1 - Black Star Markena - was a Smart Girl - she started right out using the nestbox and hasn't missed a day (except the Sunday we had temps near 100)for a week now.
For #2 my money is on my Delaware Salad who has the most developed & reddest comb & wattles next to Markena.

I tucked them in last night around 11P and everyone was on the roost.
This morning - around 6A - when I opened the coop "someone" had laid an egg from the roost.
It was laying on the cinderblock side of the partition they roost on and I thought it would be cracked or broken.
But when I picked it up it turned out to be a soft-shelled egg - perfectly shaped & intact but squishy : P.

How long can I expect this to happen?
Should I move something egg-catching soft underneath the roost?
Put her into a nestbox at night?
Ideas?

 

[cmom]

I found a few in the beginning.

 

[Kiwi Chicky]

Make sure they have access to some oyster shell for calcium, so they can form the shell properly

 

[2DogsFarm]

Quote:
All the other eggs have been fine - in fact the shells are a lot thicker than storebought eggs.

I'm starting to think this was the Black Star's first "oops" egg as there was no egg in the nestbox yesterday afternoon.

I will be picking up oyster shell at the feedstore anyhow.