Didn't know in which section I was going to post this . . . then I came across your post. I too am having trouble getting my head around this sudden death thing!
Like your girl, ours are all doing great . . . we like to think we are doing everything right. Coops and runs are secure from predators, I keep a list posted on the fridge of acceptable & unacceptable foods, we check on the girls (9) all through out the day (hubby is retired), they have free range time most everyday (always with supervision), and they lay eggs like champs.
So what happens? As we were out cleaning/feeding/watering yesterday we noticed the one coop/run with 4 girls had a lot of activity going on, a june bug had flown in the run and everybody was running around trying to get that big juicy bug, and we're laughing because they should all know by now Nugget (Barred Rock Banty) will get it, she always does! Bug flies into the coop and we hear this gosh awful squawk - figure someone is bragging "I got it!", then only 3 hens emerge from the coop. Few minutes later I think that's weird and check inside and find my beautiful Lacy (Silver Laced Wyandotte) dead of a broken neck! I am just numb - how could this happen? We've had our coops/runs for over 3 years now and felt we were accident proofed.
lisamayc, I know this doesn't answer your question - but I hope sharing helps - sometimes there are no answers - no one did anything wrong - I guess that's why they call them "accidents".
Sandy