I recently had a chicken die suddenly with no known cause also. There is just no way to know without a necropsy when there are no injuries or symptoms. If I had a second one die that way shortly after, I would send the second one in for a necropsy. When it's just one, I don't feel the need to know. Sorry I can't be more help on this. Maybe someone else can give you some ideas. So sorry you lost her so young.
Ours only get some scratch, a flock block,their feed and occasional veggies and whatever they might find in their run like bugs etc.
That happened to me a few weeks ago. I had a perfectly beautiful chicken die in three hours from the time I last saw her. The only way to find out is to send her in for a necropsy.It’s really a good thing to do if you have other chickens in case there is something infectious going on and just for peace of mind it is nice to know what happened. They test for everything, so you will know whether your chicken has parasites or disease and to possibly treat your others.Today at 9 am I went back to the cool to gather eggs. I found Walker my one barred rock hen who is about 6 months old dead on her side. No injury,not egg bound, abdomen was still warm but legs were stiff, eyes closed.She was one of my kids favorites not sure how I'll break the news to them and no idea what happened the other 23 hens are fine. No sign of disease either. There has been one hen laying monster sized eggs and there was one of those in the coop under another hen when I found her...can laying too big an egg kill a hen? What other causes can there be? Absolutely no sign of distress.
Scratch, flock block and veggies in a confined flock, I would consider treats and would need to be limited. Any time you give anything "extra" it dilute the protein and/or nutritional content of their feed.
Scratch they only get a very small handful every other day for what was 26 now 25 chickens
Thank you
