Vet not sure, last treatment options?

[Jaxx2]

My 6 going on 7 year old Rhode Island red hen has been struggling with balance and cloudy eyes for the past week and a half.
It started very subtly and little by little gets worse each day. By now she's not walking much and her eyes have gotten much cloudyer but still eating and drinking. Poop looks normal. She hasn't slowed down at all. She's still as feisty as ever- she just cant keep her balance and is uncoordinated.
I took her to a vet a few days ago- no signs of infection
Vet wasnt sure. Guessed mareks or cancer (maybe)
Vet put her on anti-inflammatory and antibiotics.
Unfortunately I don't have much hope for her. Her movement is declining.
Just wondering if there's any other last things I can try? Any guesses on what it could be?

 

[BigBlueHen53]

Post pics of her eyes? Any other chickens showing symptoms? Is she still laying eggs? When is the last time she laid? Could just be cataracts and old age.

 

[Jaxx2]

Post pics of her eyes? Any other chickens showing symptoms? Is she still laying eggs? When is the last time she laid? Could just be cataracts and old age.

No other chickens showing symptoms. She hasn't laid since sometime last year. Old age definitely crossed my mind but 2 weeks ago she was perfectly healthy. Walking just fine. She's progressed so quickly.
As for her eyes. They're subtle. Under bright light it's easier to see the cloudyness. She's molting as well.

 

[BigBlueHen53]

The thing is, as you probably know, chickens, as prey animals, are amazingly good at masking symptoms of illness and/or weakness. It's a survival strategy. To show weakness is to wave a big red flag that says, "Yo, Predators! Fresh meat here!" So it's not surprising that she's giving you mixed signals. She's doing her best to appear hale and healthy even as she's slowing down and declining, but you, who know her so well, are picking up on subtle cues. So, how long does she have, and can you keep her going? She has as long as she can keep up the charade until pain and weakness overcome her and you might find her dead some morning. Should you try to keep her going as long as possible? That's a judgment call on your part. It can be hard to tell if she's suffering, but if it becomes obvious that she is, you know what kindness requires.