Chicken slowly declining, not sure why

[Katootles]

Hi,
I have a 20 month old Austra White hen "Spot" I raised from a day old chick who has been slowly deteriorating over several months.
Symptoms:
-Very pale comb (growing paler over the last several weeks)
-Lethargic (now she just sits in the coop, but she was free ranging a few days ago, albeit moving slowly and panting if she moved too fast)
-Eats but not much and isn't excited about treats like she used to be
-Hasn't laid in at least 6 months
All of these symptoms have been slowly coming on over the last few months. I have checked for mites, ticks, etc and no worms in poop. In fact her poo seems pretty normal. The rest of her flock have no health issues.
I honestly keep thinking I will find her dead one morning but she just keeps on and says hi to me when I check on her.

A little background: she did injure her foot in November 2018. She was limping significantly but still able to move enough to eat and drink, but stopped laying, and never returned to laying. I treated her best I could and her leg healed after several weeks. But then she began having the beginning of the symptoms I mentioned above.
I really have no idea what's wrong with her or if she has a treatable disease. Any ideas?
Thanks so much for your help.

 

[Cyprus]

Did you check for bumblefoot?

 

[Katootles]

No signs of bumblefoot

 

[Kiki]

How does her belly area feel?

Compare it to another bird...see if it feels full and hard like or full and squishy like.

 

[Kiki]

Also it's worth mentioning that 8 times out of 10 you won't see worms in poop until bird is so infested with them that the worms literally have no more room to stay inside.

Not laying eggs is not a good sign... Reproductive disorders are very common.

 

[littlefarmgirl9]

My apologies for you and your sick hen! I lost a Black Australorp recently to reproductive cancer, and she exhibited all of the symptoms you described. She also had bouts of sour crop throughout her life, leading to weight loss and malnutrition. Your best bet is probably to just keep her comfortable, and ease the pain of any symptoms she may be exhibiting.
Sorry to be so bleak. Good luck with your hen!