My chook is suddenly blind in one eye... what causes this?

[Highland Brooke]

Hi all I've noticed that one of my chooks seems to be blind in one eye all of a sudden. The pupil is a pin prick size. No other chook in the flock is affected, and the affected chook seems to be eating and behaving fine... although I can clearly see that she is only using her other eye to find food and navigate around, she's doing this considerably well! I have no idea what could have caused this... does anyone know...? If I can heal her eye that would be great, but just to know the possible causes of it would be great. Thanks all

 

[nuthatched]

First thought is mareks but I think there's a few other issues that can cause that and I don't want to be jumping the gun.
I hate to bug you, but I believe you've had first hand experience? @azygous

 

[coach723]

Hard to tell from the picture, it looks like some glare on the eye, makes it hard to see. Some common issues are pupil changes and sometimes graying of the eye from Marek's disease, cataracts, or an eye injury from being pecked or otherwise hurt in the eye. If she can see with the other eye then she can adapt. But I would keep an eye on her to make sure she isn't bullied, kept from food, etc. since she's at a disadvantage not being able to see something coming from that side. If she free ranges she's at increased risk from predators.

 

[Connemaracait]

My cockerel has one eye that suddenly looks like your picture with a pinprick pupil not reacting to light and very slightly sunken. He has been like that for a couple of days and seems blind on that side. How is your bird now? Is it permanent or did it improve?