Sorry to hear that.. Consider the reality.... Battery hens are past their prime when you get them... These choice egg production hens are not known to have long life spans.. The heavy duty egg production just burns them out.. I think your hen may be leaving due to natural callings. Just provide her with all the comfort you can.. YOU WILL FEEL BETTER AND SO WILL YOUR HEN. I always break down when I loose one of my pets. It is just a SAD REALITY.
WISHING YOU BEST.
When you have room, take in some more of the retired hens, and make their GOLDEN YEARS as pleasant as you are doing now. I don't have access to battery hens where I live, and also the limits on number I can house. I was able to adopt 2 banties this summer from a very nice person here on BYC also. Pix below.
But I have taken in stray dogs, and those cats in my avatar??? They are feral cats that have been FIXED .. They actually have never been broken, but you get the picture. I do feed them and they just wont go away. ( of course they got their shots at the vet )