:hugs I'm so sorry
How long has it been since she's not had anything to eat? Have you tried tube feeding her?
It's heartbreaking, but sometimes no matter what we try, they continue to decline and we have to come to a place where a decision needs to made made whether to continue on or let...
Yes, her age does need to be considered. Sadly, she's an old hen and it's very possible that she's coming to the end of her days.
I'm so sorry, I know it's discouraging that nothing is working:hugs
Smelly breath is due to something. A crop does not have to be full to be sour - having a sour crop is like having a yeast infection - sometimes birds will not eat because of this.
If you detected an odor, then I would start treating for sour crop.
https://www.backyardchickens.com/articles/how-to-treat-sour-crop-and-impacted-crop-and-how-to-know-which-one-youre-dealing-with.73607/
I know you've looked inside the beak before - her acting like the tongue is swollen, is it? Perhaps a hair or small string is wrapped around it? It happens sometimes.
If she seems to do better outside, is there a way to put her back with the flock during the day? Not sure if she will be picked on from being separated, you will have to watch for that. A large dog kennel set-up within the run works well, to keep one "separated".
Sometimes chickens find...
I'm so sorry she's not getting better.
Can you get someone to hold her and you take another look inside the beak just to be sure there's nothing in the throat, roof of the mouth, etc. that may be preventing her from eating?
I would look inside her ears while you are at it.
What is a "regular" respiratory infection? Chickens for the most part have respiratory diseases - Mycoplasma is fairly common (another name for it is CRD=Chronic Respiratory Disease). Symptoms include watery or bubbly eyes, sneezing, mucous, lethargy, going off feed, coughing, etc. Without...
Was her crop empty this morning before she had anything to eat/drink?
Have you looked inside her beak for any canker, plaques or yellow/white cheesy material?
I'm sorry about your hen.
8yrs is getting on up there in years. Does she still lay eggs?
I would check her crop first thing in the morning before she eats/drinks to make sure it's empty. Let us know what you find out.
I would also check her for lice/mites, inspect her to see if she's...