Neurological symptoms quick death

[Naturalness]

One of my young hens died at about 6 weeks age. She looked fine, alert, but strangely unflustered when I picked her up, normally being very shy, because I noticed something wrong with her. Her legs were useless, not totally paralyzed but not able to stand her up anymore. I isolated her and provided her food and water. She accepted both though not overly enthusiastic. Her feathers and general appearance did not indicate malaise. Her comb was normal, her eyes were normal.
I had to leave for the day and when I came back 10 hours later she was dead.

I suspected Mareks but felt her age made it unlikely and the progression had also been too fast. I suspected botulism but can't for the life of me figure out how only this one would have gotten it if they're all eating the same feed in the same nursery area. Still with how fast she died it seemed the most likely or something similar at least.

This was three weeks ago and today another hen from the same batch seems to have the same problem. She can still stand but her legs give away. I isolated her again and gave her water & food, which she went for vigorously. Comb and wattles are red and her feathers are smooth. Again she seems less responsive when I or the dogs approach which normally would have sent her into a frenzy. But other than that she doesn't appear sick.

Does anyone have any ideas? I'm guessing that by tomorrow evening she'll have died just like the other one. I could perform an autopsy but I don't know what to look for... we don't have any poisonous creatures or plants here worth mentioning and all my young ones get the same feed. I'd like to know what I'm dealing with since trading chickens was part of my set-up and I obviously can't do it if there's a chance I'm giving others Mareks or something similarly undesirable. Any ideas appreciated

 

[azygous]

You are correct that these chicks are too young for this to be from Marek's.

I've had experience losing chicks to the symptoms you describe. One day, I was sitting in the run when an eight-week old chick came in and collapsed at my feet, literally its legs going out from under it. The chick died later.

That triggered a three-day investigation of all possible hazards that could be responsible. Just as I was going over all of the same territory for the sixth time in three days, my eyes landed on the log splitter sitting in the yard with chickens all scratching around it. I recalled see that little chick under the splitter just hours before it collapsed at my feet.

The ground under the splitter was soaked with hydraulic fluid. The sirens all went off. That was it. The petroleum distillates killed my chick and had made several adult chickens go lame. I immediately moved the machine out of the area and dug up all the contaminated soil.

I've also lost chickens to insecticides. The symptoms are the same, and death comes just as quickly after exposure. One of the things we may do is to spray insects in soil in a garden pot and then later water it. A chicken comes along and drinks from the puddle under the pot as it drains onto the ground. A few hours later, the chicken is dead after first losing control of its legs.

Finding the culprit may not be as easy as it sounds. We tend to insist on denying that we would ever do anything to hurt our chickens. So you need to accept that a human mistake may have occurred and be open to it when you see it.

 

[Naturalness]

Thanks. While I can't immediately identify any source of potential poison at least it's something that can be fixed if found, and more importantly can't be transmitted...

Is there anything else it could be and ways to reduce the suspects? I just really want to make sure I'm not harming other people's flocks. I've seen what introducing a sick bird to a new flock can do and it's not funny at all!

 

[azygous]

Mold is the only other thing that causes paralysis in young chickens.

Avian viruses start producing symptoms between eight weeks and five months.

There is always the truly freaky. Years ago, I had several baby chicks find a buck moth caterpillar and they pecked it. It had a powerful venom that caused instant neuro-symptoms and death.

 

[Naturalness]

I might have an idea of what could have caused poisoning: my feeding bowl was relatively close to the water bowl and some of the feed had accumulated underneath the water bowl that was resting on a plastic plate keeping the water with the feed. This would have been exacerbated by rain which we had right before the chicken got sick.
Not sure how I missed it, but as I cleaned out the nursery coop now looking for the culprit I finally noticed it and it not only smelled rotten but there were maggots in it too. I guess the chickens mostly ignored it but this one maybe didn't. Does this sound like a likely cause?

 

[azygous]

Yep, it could be if mold and bacteria were present. Wet feed and maggots on their own wouldn't. But, yes, it's a small clue, but it's enough.