Cause of blindness?

[fatcatx]

We put our 2 yr Welsummer down today because we discovered she was blind in both eyes. 4-5 days ago she was seeing well enough to jump and grab bread from my hand. No way to know if she was seeing well then or just had adapted to judging distinct shadows.

Looking back over the last 4 days I realize there were little signs that something wasn't right but I was not clueing in. I feel awful for not picking up on the signs sooner. Does anyone have any idea what could cause this? I am worried it was something she ate but the other birds seem fine.

 

[Eggcessive]

Did her eyes look any different than usual as far as color in the irises or the pupil size or shape. Was there any clodiness inside the dark pupil? There is a good thread by University of Florida about "common eye disorders" if you Google it. Common problems can be eye infections, high ammonia levels in the coop that may lead to abscesses in eyes, cataracts, vitamin A or E deficiency, avian encephalomyelitis (AE,) and in certain diseases such as Mareks.

 

[fatcatx]

Thank you for the reference info. It has been very helpful.
Her pupils were dilated but did not show other signs of illness. She was not showing any other symptoms of Mareks that I could see. I've been reading pages and threads all afternoon. I will have a necropsy done in the hopes I can exclude Mareks as the cause. The reading left me depressed and didn't answer a lot of my questions.

1. If it is Marek's, was it just bad luck? Our flock is half birds I hatched myself and half feed store chicks which typically vaccinate for Marek's. No adult birds have ever been brought in. Wild birds are rarely in the yard. We live in the city so there is no flock within 6+ houses of us that has poultry. Given all this we should be low risk.

2 Outcome for the future? It sounds like that even if we started with a brand new flock, they would likely get Marek's from the environment? Would chicks be "safe" from exposure if brooded in a separate barn or garage?

I hope the test comes back as clean. I don't know if I want to continue to keep chickens if so many will die every year.

 

[fatcatx]

Another thread had this image showing ocular Marek's. Her eye looked nothing like that. Color and clarity were normal. Her pupils were just large for a sunny day.

Does oculars Marek's always look like this? It would be nice to take it off the plate of possibilities.

Grrrrrrrr miserable tablet will not post pic. I copied it from another thread. I'll post as soon as I can get to a PC.

 

[fatcatx]

Here are some ocular Marek's photos. Her eye looked like the healthy examples on the left. Given that, can I presume her blindness was caused by something else?
I was literally planning on getting a few fall chicks this week to boost my eggs numbers this winter, but now I do not feel safe getting them until I figure out what is going on.

 

[Eggcessive]

Blindness seems to be a very common problem occasionally with one chicken in a flock. Because it can be from infections, cataracts, vitamin A or E deficiency, or injuries, it may just be a singular occurance, and nothing to worry about. You might Google "blind chicken" and look for BYC posts.

 

[fatcatx]

Thank you E for the reassurance. After reading everything I could get my hands on, the two most logical culprits would be worms and/or vitamin deficiency.

They of course eat a quality layer feed and I have not seen any signs of worms. Is it even likely that she had a worm load so bad it could cause blindness when there were no other signs? I almost wish the fecal test comes back positive. At least then I will feel like I have an answer.

 

[Eggcessive]

Eyeworms in chickens are very rare, and there is a lot of bogus information about them. Usually they are found in tropical regions where the surinam cockroach is found. Some of the so-called eye worm videos are actually respiratory diseases that have caused a puss-filled eye from conjunctivitis.
I hope that others whose chickens have faced blindness will chime in. One may never find the reason for blindness.