Blind hen

[earlybird10842]

Several years ago, we got five hens of a commercial laying breed. After they hit about four years, none of the four we still had were very healthy, and three of them died--two from Egg yolk peritonitis, one from something that I now am thinking was also caused by an egg yolk peritonitis-like problem. (And I made the decision that multi-purpose birds were the thing for me--anything but Egg yolk peritonitis!) We have one hen remaining. For a while, she was very healthy. Then she suddenly decreased activity. It took a few days to realize she was blind. It appears that she still has some sight in one eye and can see light in the other, but for the most part cannot see. She still eats and drinks, she knows the layout of the coop, run, and the area around it. We have put her in solitary confinement as the other birds will peck her to no end. Today she laid an egg (!)
My question is, what caused this blindness? Was it her heritage? Her eyes are blue and cloudy, but there doesn't appear to be damage. Can chickens get cataracts?

 

[Eggcessive]

Yes they can get cataracts, and there can be several causes of blindness. Vitamins including E would be helpful. Here is a good link or 2 to read:
http://edis.ifas.ufl.edu/ps031
http://www.joneshamiltonag.com/jh/wp-content/uploads/2011/10/PLT_Poultry-Eye-Disorders.pdf

 

[earlybird10842]

Yes they can get cataracts, and there can be several causes of blindness. Vitamins including E would be helpful. Here is a good link or 2 to read:
http://edis.ifas.ufl.edu/ps031
http://www.joneshamiltonag.com/jh/wp-content/uploads/2011/10/PLT_Poultry-Eye-Disorders.pdf

I really doubt it's mareck's--or any other virus or bacteria--as I do not know of any flock they have been exposed to that may carry it. I have always kept pretty good biosecurity practices and the last time we added to our flock was over a year ago from a very healthy flock. So I pretty much think it's fugus or vitamin deficency. However, the eyes are grey, but gray can mean cataracts, correct?

 

[Eggcessive]

Cataracts are cloudylooking over the pupil. Mareks can cause gray eyes--is there anything irregular about the pupil--odd shaped pupil or pinpoint pupils? Here is a link showing some cases of Mareks, and the picture below on the right:
http://partnersah.vet.cornell.edu/avian-atlas/search/lesion/464

Eye on the right is Mareks disease

 

[earlybird10842]

Cataracts are cloudylooking over the pupil. Mareks can cause gray eyes--is there anything irregular about the pupil--odd shaped pupil or pinpoint pupils? Here is a link showing some cases of Mareks, and the picture below on the right:
http://partnersah.vet.cornell.edu/avian-atlas/search/lesion/464

Eye on the right is Mareks disease

Hmm...the pupils are irregular, however, it doesn't look like the pic on the right--more like cataracts, to me. Also, top of the beak is overgrown. In the pictures,each chicken had an irregular beak. Is beak an indicator of Mareck's? Should I check the rest of my flock for strange pupils? I have not noticed anything. This hen seems like she has cataracts.
Thinking about it,there may have been continual eye damage, so I am wondering if the other chickens have pecked her shiny eyes soon after cataracts took over, and she couldn't dodge because she was already partially blind.
If this is mareck's, is my flock already all infected? How did it infect the oldest hen and not the others? What should I do to complete a diagnosis?

 

[Eggcessive]

Normal eye in middle, Mareks on left and right

Cataract from avian encephalomyelitis on left, normal pupil on right

 

[earlybird10842]

Cataract from avian encephalomyelitis on left, normal pupil on right

Yep, that's what it looks like. Complete with the darker white spot in the middle.

However, it is very unlikely avian encephalomyelitis was somehow transmitted into our flock. The last time we added babies was two years next spring, this bird is over four years old and all of the other birds are perfectly happy and healthy. Can cataracts look like that without being from AE? Genetics, perhaps? From the fates of her flockmates I can judge that these birds probably have genetic problems.

 

[Eggcessive]

In thelink in post 2, it talks about vitamin E deficiency, AE, genetics, and continuous exposure to light 24 hours a day as some causes. I also think that injury is a common cause.

 

[earlybird10842]

In thelink in post 2, it talks about vitamin E deficiency, AE, genetics, and continuous exposure to light 24 hours a day as some causes. I also think that injury is a common cause.

Vitamin E deficency--we don't supplment feed, so possible/probable.
AE--probably not
Genetics--Yeah, probable/possible
Light--No.
Genetics--probable.
Injury--probable
Combination of various causes--my conclusion.