I wanted to add that my chickens have not shown any of the common nerological or ocular symptoms and seem to have only these visceral lesions.
Scaley was the first to go. She was slow to gain weight after I had her for about a month. Never sexually developed but was probably about to when she passed. The others, even the Nuzzler who was younger by a week or 2 were already laying. She was doing the mini molt they do before coming into lay when she passed away. Her blue feathers were coming in stress barred. Great vision, fastest and most agile, most personable bird ever.
Her report is attached and you can find the post I made for help and story here:
https://www.backyardchickens.com/threads/tail-injury-with-swelling.1680993/
Dove's kidneys, ovaries, and intestines were affected but her liver and heart looked good to me. When Dove was a chick she did have trouble connecting with bits of food on the ground or floor surface but could grab something held at or above head level. She got over it as she came into puberty but only laid eggs for a short time. She always had watery diarrhea from a couple months old but butt feathers stayed clean. She developed an infection on her drumstick towards the end of her life and was lame but had a good appetite and loved dust baths even when she needed help with them. She had a stress molt that she wasn't old enough for. I never thought to look closely for stress barring on her white and blue splash feathers so I don't know about that.
Big Red was the picture of health and never laid an egg that wasn't perfect. She was actually Miss Perfect in every way. Never had an issue growing up or laying until the end.
She suddenly stopped laying and started getting ascites and slow crop. She started to molt but her feathers were coming in stress barred.
She went downhill fast with no appetite and self isolating. I regret trying to help her with torpedo feeding once I saw what was going on inside.
The Nuzzler is in hospice now and has always had trouble connecting with small bits of food but it didn't slow her down with weight gain or activity. She is the largest bird I have/had but not fat.
She had an early molt and stopped laying when I took my first to die Scaley inside to treat a lesion/cyst on her tail. She has patterned feathers so I don't notice stress bars. She started laying beautifully again and was just fine until about a week ago. She got diarrhea and stopped laying and is now lethargic with no appetite. Appetite for food and water disappeared yesterday with some fake eating. She has not eaten or drank today even with some encouragement and I will not force her because I know it is futile and probably painful.
Edit: We ended The Nuzzler's suffering at 7PM and I noticed a newly grown stress barred feather on the back of her neck. Her necropsy will be in the morning.
Cleatus the rooster seems fine but his feathers are showing stress barring. He is on the floor of my bedroom just hanging around Nuz. I took him in to see her this morning but she just sits and when I put him back outside he stayed by the front door making noises. He came back in on his own and doesn't want to leave or be alone.
I am going with stress molting/stress barred feathers as the only consistent early sign in my flock so far.
