One of my hens has developed very different sized pupils, with her left one being even in shape but a great deal smaller than the other. She seems to be more nervous than she used to be, but this could be as a result of having moved and them being in their own area rather than sharing the whole garden with me as they did. She has not had anything to indicate there might have been a problem with her eye before this, and seems well in herself. Any suggestions as to why this might have come about, and if there is anything I can do for her? She does not appear to be blind in that eye, though on closer examination the pupil has 3 greyer areas that come out like fat spokes. Am investigating the Marek's possibility but as there appears to be nothing else wrong, it's rather hard to be sure. All ideas/suggestions welcome - thanks. She is around 18 months old, if that makes any difference.