Soft Shelled eggs - several weeks now

One of my hybrid girls who has previously been a good layer has started laying soft shelled eggs, so soft that the egg does not hold its shape and collapses. Shes about 13 months old and there is always grit available, they have access to roam on grass and regulary get "treats". I've started added a mineral supplement to the feed that has a47% calcium  content but were still getting soft ones 
Any one got any ideas ?

grit is not the same as calcium - for this they need either washed, baked and crushed egg shells or oyster shell. To absorb the calcium they need a source of Vit D so I would suggest hanging up a cabbage for them in their run. If after trying this then see if giving her a tiny pinch of limestone flour onto something like a half a grape for about a week sorts her out.
The grit is to help them digest their feed as they have no teeth.

i was getting same thing. cut everything out (treats) then introduced one thing at a time. came to the conclusion it was the garlic. cut that out and been ok since.

Adding a little cod liver oil to their feed once a week will really help calcium absorption.

Battles Poultry Drink contains phosphorus which is also essential for calcium uptake.

Adding a little cod liver oil to their feed once a week will really help calcium absorption.

Battles Poultry Drink contains phosphorus which is also essential for calcium uptake.

great tip aunt sally thankyou, i have loads of cod liver oil in the house for our dog, so will try this myself.   nickyx

crushed eggs mixed into the food with a bit of Cod Liver oil seems to of stopped the soft shell problem as no evidence since, although........it now loooks like the hen who was laying the soft shelled has stopped laying  oh well !!!