Sudden blindness, diarhea, cyanosis - no idea what's wrong

[Kraken_rises]

Hi, any help appreciated. I'll try to be brief.

Hen is 2.5 years old, she's a small breed 'Gingernut ranger' not bantam small. I don't have others to compare weight but seems skinny.

Been off lay for a while, bit of a cough a few weeks ago but no other signs of illness and seemed to be preparing to lay again. Tuesday she was running around fighting for treats.

Found yesterday (wed) hiding and seemed unsteady, thought possibly egg bound to gave Epsom bath and had a good feel around but no egg that I can detect. Seems to be in pain when touched but also off balance.
Put her in a crate and left her, didn't seem interested in food drink. When I tempted her she seemed happy to drink and eat but I realised she couldn't see the bowls. She will peck at air beside bowl if moved until I place it where pecking. Eyes are clear, pupils normal but less responsive, seems to see some movement only.

Her comb is turning blue but no breathing distress. Poop is very watery and mostly white with some small amount green.

Thirsty this morning but can only be tempted with small amount raw egg, seems to turn away from food. Literally bangs into bars of the crate.

Can't find anything that matches symptoms, any ideas?

 

[Freeloading slacker]

Hello I've heard of somewhat blindness in chickens when there is a vitamin A deficiency, you should try adding some vitamins in her water.

 

[Freeloading slacker]

It can also be caused by poor ventilation.

 

[Kraken_rises]

It can also be caused by poor ventilation.

Thanks for the suggestion, I considered vitamin deficiency but they seem to have weepy or crusty eyes. Besides she's been eating fresh layers pellets and also getting extra greens etc. The ventilation is possible but coop kept clean and reasonably ventilated, I say possible because she may have slept in the nest Tuesday night which is much lower. Can't imagine such a sudden change with no visible irritation though. I'll keep both ideas in mind.