Yes soft shelled eggs are laid occasionally when the hen has not been fed enough grit. As Aunt Sally says make sure your hens get plenty of oyster shell - you can buy it from agricultural shops, I suspect also from pet shops, and I think also from Eglu.Alternatively you can crush up hens' eggshells and feed them back to the hens - but if you do that you must make sure you have baked the shells in the oven so they go under a temperature high enough to kill any nasty bugs. It's important to get this lack of grit sorted out because if a hen gets really low on it she will eventually start taking the calcium from her own bones to use in shell production, which will make her weak and fragile.
Incidentally there are 2 types of grit that hens need - oyster shell is one sort - that's for eggshells ... the other sort they need to eat to go into their crops to grind their food up being as they do not have teeth! You can buy this from the same places I mentioned above or you can just let the hens scratch around and pick it up themselves in the garden. If you have a small run like an Eglu that won't be enough, so you will need to let them forage in the flowerbeds and soil to pick it up.
Good luck with the eggs!!
