Dead pullet, looking to know what happened to prevent from happening again

[jklhgyfhg]

I am a first time chicken keeper. I feel awful that I lost one of my pullets, she was a 4 month old Black Australorp.

The evening before I found her dead in the run I knew something was wrong, I had picked her up to check her over as usual and was stroking her silky soft feathers. I handed her over to my partner, and as soon as he had her in his hands, a brownish clear liquid came flowing out of her mouth and onto the coop floor. When he set her down, she stood still for a moment and then went over to a (lower) roost and perched there. I made a mental note to check on her again in the morning.
In the morning when I let the birds out she was the last to leave the coop, which was unusual for her. I had to leave for a few hours and when I returned she was laying dead beside a tree.

Her behaviour up until her last evening was normal, she was drinking plenty of water, eating normal amounts of food, loved foraging in the run and had a healthy curiosity and energy level equal to the other birds in the flock. I checked her and the others every day/every other day for mites or abnormal swelling. Was there something I missed?

I'm just looking for some guidance to know where my mistakes as a first timer were made and how to prevent them from happening again.
Thank you

 

[Isadora]

We can all speculate, but unfortunately we wouldn't know for sure unless you sent her body in for a necropsy.

 

[BlindLemonChicken]

Unfortunately sometimes chickens die and the cause isn't at all obvious or even discernable without a necropsy. She could have gotten into something, she might have had sour crop (although that is usually something you would have noticed before and takes a long time to kill a bird) or she might have injured herself somehow internally. I have found chickens dead in the run a couple times with no apparent cause when no other birds are sick and they seemed healthy the morning before. Its sad and we all try to avoid it but sometimes it does happen.

 

[Eggcessive]

With the brown liquid coming out of her crop she might have been suffering or getting sour crop, or perhaps her crop was not emptying normally. When we pick them up, sometimes we accidentally squeeze the crop, and it’s contents may come back up. Did the crop contents smell sour or bad? Most state vets will perform a necropsy M-F if the body is kept cold and taken in or shipped overnight to them. Sorry for your loss.