I hope I'm not doing anything wrong here, if so mods please delete. On a well known chicken page I saw a picture of a chicken with spots on her iris, well at least it looked that way to me. I've only lately gotten into researching signs and symptoms etc of all the different chicken diseases so of course I thought it could be mareks The owner of the page said it wasn't, and they seem to know what they are talking about. Edit: I did notice it doesn't have the grey colouring, its only spots. So I'm wondering if you often see this kind of thing without it being mareks (just like every time I get a cough it doesn't mean I have lung cancer ). I have taken a small crop of their photo which I've posted below. If this isn't allowed then please delete.