Just discovered this thread; it's the closest thing to my own experience.
We bought 3 grown laying Rhode Island Reds about 5 months ago. All had a normal and healthy egg production, UNTIL one of them jumped the fence to be gently 'mauled' by the neighbor's dog, a playful Border Collie. Well, "Heather" lost some feathers but otherwise seemed OK. But, I think it was right away when her eggs were PARTIALLY formed. The 'lower' half would be soft, but crackable, while the top would be gelatin. It is still like that after probably 3 months. We have dutifully supplied assorted water additives, food supplements, oyster shells, feed with calcium, egg booster, etc. No change.
So here is a premise I wish to introduce: what if the 'mauling' event caused stress or injury to result in a lack of 'dwell time' in the oviduct where the calcium is stimulated? Really, it's the only thing that makes sense to me. I know that there are valves at both ends of the stomach, that, when not working properly can cause acid reflux or inadequate digestion (diarrhea).
This is my first year as a chicken rancher.