I'm clinging on for dear life that this is what my Bella's got! From what I've read, it is characterised by thin and shell-less eggs, but no other outward signs of illness in the hen. (This is what distinguishes it from infectious bronchitis, salmonella, e-coli and mycoplasmas, all of which can also cause egg quality to decline but which also cause varying symptoms of acute illness in the hen too.) It is caused by a virus originating from waterfowl, but is commonly found in chickens, especially in Europe. It may remain latent in a chick which has been infected through the egg until that chick reaches maturity and commences laying. I also hear that it is only likely to last for four to ten weeks, after which the hen fully recovers and egg production gets back to normal. Although my Bella did have a problem with egg binding as a result of the soft shells, and has a constantly wet vent from all the straining and watery poop that accompanies a soft shelled egg, she's otherwise been completely healthy throughout. She also goes through phases of laying 'good' eggs - varying from a ratio of three good then three soft, to one good then six soft. Can anyone add anything to this for me? Anyone experienced it in their chickens and had a positive outcome?