Just a quick up date on how we have managed the egg eating problem. We have found that the problem only happens if the culprit can get back to the nesting boxes on her own. Now we do not let any of the hens out of the immediate confines of the run until they have all laid and we have collected the eggs - and only then open the gate so they can range freely over the paddocks . With the other hens present in the run the pecking has stopped.
I have watched this over the last few months and it is consistent behaviour.
It can only work as a system when all of the hens are laying everyday and I know that I have got them all of course but thought I would post in case it is of interest to anyone.