Soft Shelled Eggs
From Omlet Club Wiki
A thin shelled egg is one that has such a thin shell that it may crack or break when picked up. This is a photograph of a thin shelled egg where the shell was so thin that it dented as it was picked up. The picture on the right is of mis-formed and soft shelled eggs.
A soft shelled egg is one that has the shell either totally missing or resembling a fine soft membrane. It may look like a blob of jelly with a yolk. The egg usually breaks and the soft shell then just looks like a wrinkled piece of material.
Occasionally a hen appears quite ill, quiet and hunched for an hour or so before a soft shelled egg is laid, but then recovers completely soon after laying. A hen that behaves like this occasionally may have produced a soft egg that is eaten before you see it. A clue is the quick return to absolutely normal activity and behaviour.
 Frequency and Possible Causes
It is quite common for a hen to very occasionally lay a thin-shelled or soft-shelled egg. A few hens do this for a short while and a very few may do this for several weeks.
This is extremely unlikely to indicate a problem with a hen. The one-off dodgy egg is just a blip in the egg production system, possibly caused by a shock, but usually no cause can be found.
09/06/10: A shock can be a mild as a sudden downpour of rain. We probably wouldn't think twice about it but to a chicken, it must seem as if the sky is falling down! When homing your chickens, be aware of such things like:
- are you near a place where game shoots take place? - is there a bird scarer in a field near you? - do lorries thunder up and down your road? - when you stack things up in the garden, could they fall and make a noise?
If you do get more than one thin/soft shelled egg from a hen, you may find it helpful to review the amount of calcium your hens get in their feed. A good quality layers mash/pellets should contain enough, but hens that eat a lot of other things while free ranging, or get lots of treats may need extra calcium. You can buy poultry grit or oyster shell from feed merchants, or you can recycle your own egg shells. Just bake them and then grind them up.
A few people have noticed that their hen looks 'poorly' and is quiet and 'hunched up' for an hour or so before laying a soft shelled egg. The hen then makes a miraculous recovery after laying the soft egg. This is nothing to worry about.
Some people have used Shellstim, a liquid which you add to the hens' drinking water to provide extra calcium. No longer available. Zolcal D or Davinova C can be used instead.
Adding Limestone Flour (calcium carbonate), which you can get from equestrian suppliers, to their feed is another way of getting extra calcium into the hen.
Not only do the hens need calcium to form good quality shells, but it is also vital in the process of enabling the muscles to contract to expel the egg.