Soft Shell Eggs

[British Raj]

I have 4 hens - they are Wyandotte bantams. The mother is 18 months old. The three daughters are exactly 12 months old tomorrow! One of my girls has laid 3 soft shell eggs in a row in the last three days ... one each day. She is the runt, smaller than the rest, and has laid funny shaped eggs before ... thin and long but not soft shell. Once she lays the problem egg, she is fine and carries on as normal.
All the others are laying fine and they are on the same diet ... layers crumble + lots of foraging in a large garden. They also pick up some sunflower and wild bird seeds and meal worms if they drop from the bird feeder. I also regularly give them outer leaves from greens and some grated carrot. It is painful to watch as she can't push it out and struggles with it for a good hour or more. To top it, today's egg is not to be seen ... looks like one of them ate it so I am concerned that they will all start pecking each other's eggs now.
How can I fix this please?

 

[Icemaiden]

Do they have free access to oystershell grit?

 

[British Raj]

Yes, they have a tray of mixed grit to hand all the time ... The hen has now stopped and gone off lay. And she s absolutely fine otherwise. Perhaps it was just a hiccup at the tail end of a laying cycle. She hasnt gone broody either. All is well.

 

[Marigold]

You say the mother is 18 months old and the younger ones are 12 months. That means that the older hen was less than 6 months old when brooding her clutch, barely into lay herself, I would think, and not fully mature. I just wondered whether this has resulted in at least one of her chicks showing less than optimum development? As you know, pullets eggs gradually get bigger over the first few months in lay, so larger eggs from a hen who is at least a year old are preferable because they contain more nourishment for the embryo.
She certainly sounds like a bird who is going to devote herself to a lifetime of going broody, after a start as a teenage mum!