My hen just died -- From what?
I am so sorry. That is always hard.
Five years-old for a laying hen is actually pretty old. She likely became weak from laying for all those years and may have had pneumonia, parasites, internal laying, or liver problems (causing water belly). She could have been weakened and so got a bacterial infection, as it sounds with liquid dripping from the mouth. Whatever it was, as long as you clean out the nest box, it likely won't be contagious to the other hens.
I hope the others continue to do well.
If you didn't do something with her body yet I heard once that you can do an autopsy for free somewhere then you could know for sure what happened.
I dont know where it is or what it is called does anyone else know about it.
I would also like to know what it is called. I think most places have you pay for any necropsies or blood tests.
- Master Tuber
Some states do them for free.
I'm so sorry to hear that. It sounds like some sort of system shut-down due to excessive laying. Something such as Internal Laying or Water Belly. It claims a lot of hens above a year of age that were bred to lay a lot of eggs. As winter comes and they begin molting the stress also worsens, which can make it more difficult to get past a weakness in their immune system.
Your explanation sounds reasonable though. She was 5 years old and had a good life at least. Now I only have one left. Hope she'll be fine.