Sudden chicken death with unknown cause...

[Indigopearl]

Yesterday my daughter took care of our chickens and said that one of them (Pipit) was so tired she wouldn't even come in for scratch grains and mealworms, so she carried her in. We were running late and I was making food to bring to a gathering, and then we didn't get home until late. Today our little Pipit was dead on the coop floor.

Here are all the details I can think of that might be pertinent:
* We have (had) 5 chickens (about 8 months old) in a coop with sand and an attached run. Pipit was the smallest but I never saw her picked on.
* We let the chickens forage in the yard daily while we scoop out the coop, clean up the run, and refill their food and water. Then we give them a warm mash and some scratch grains, and they run back in.
* Pipit was well enough to walk out when the door was opened, but she plopped down on the grass and didn't get up.
* She laid an egg yesterday morning.
* She had no respiratory problems, discharge, loss of appetite, or signs of injury.
* After she was carried into the run, she pecked at the bottom of the hanging waterer instead of at the nipple so she may have been disoriented.
* Two days ago, when the chickens were outside, Pipit suddenly started squawking loudly for no apparent reason, kind of like she was doing an egg song. We went over to her and couldn't see anything wrong... and she hadn't just laid an egg. She stopped and went on like normal so we didn't think anything else of it.
* She got herself into the coop before the door closed last night.
* None of our other chickens appear sick or anything. But when I was inspecting around their vents, I did notice that they all have at least some dried poop in their fluff.

I've read about every chicken problem I can find, but nothing seems to fit. I did put some ACV in their mash for good measure but I'm not sure what else to do. Any ideas or advice is welcome.

 

[Eggcessive]

Sorry for your loss. Could she have been low in the pecking order and maybe was kept from eating or drinking by the others? She could have had some issue that made her die prematurely young, but hard to know without a necropsy. Most state vets can perform a thorough necropsy along with histopathology and testing. Keep the body cold on ice in a cooler wrapped in garbage bags, ut don’t freeze it. Contact the state vet lab early in the morning and take it in or ship it overnight. A home necropsy could be done and might show something if the professional one can’t be done. Here is a list of state vets labs:
https://www.metzerfarms.com/poultry-labs.html

Here is a chicken necropsy with organs labeled if you do a home necropsy, and take pictures of major organs to post here for help. You can fast forward through parts just to get an idea of what to look for:

 

[Indigopearl]

Sorry for your loss. Could she have been low in the pecking order and maybe was kept from eating or drinking by the others? She could have had some issue that made her die prematurely young, but hard to know without a necropsy. Most state vets can perform a thorough necropsy along with histopathology and testing. Keep the body cold on ice in a cooler wrapped in garbage bags, ut don’t freeze it. Contact the state vet lab early in the morning and take it in or ship it overnight. A home necropsy could be done and might show something if the professional one can’t be done. Here is a list of state vets labs:
https://www.metzerfarms.com/poultry-labs.html

Here is a chicken necropsy with organs labeled if you do a home necropsy, and take pictures of major organs to post here for help. You can fast forward through parts just to get an idea of what to look for:

Thank you for your response and the info. I actually never saw her picked on at all. In fact, to my surprise, I saw her pick on the low chicken once or twice. I’m certain she was not being hindered from eating or drinking. I already disposed of her body because I was worried about predators being attracted to the rest of the chickens. But if this ever happens again (hopefully it doesn’t), I will reach out to our state vet lab to see about a necropsy. That was not on my radar whatsoever so I especially appreciate the suggestion.