I'm so sorry to see Mrs Lee is such a state. That must be heart breaking for you. Sadly, the most likely diagnosis is Marek's, especially when you have a history of it in your flock. It may be that this bird has been carrying the disease in it's dormant phase for months or even years. It may be that she has had a minor outbreak before and you have not noticed it. The vaccine will not prevent them from getting it but should prevent the more serious tumours. It can exhibit as something as minimal as being unable to keep one eyelid fully open and sometimes recover within a day or two when the disease goes into remission, only to resurface when the bird's system is low. Moulting or bad weather/shorter days/confinement etc are often triggers in older birds as well as the usual trigger of adolescent males running amok in the flock (not sure if any of those apply other than moult) and secondary outbreaks are usually more severe and prolonged than initial ones if they survive.
The best that I can suggest is to keep her well fed. I would give her a warm wet mash made with chick crumb rather than layer feed because it has higher protein and less calcium and she is unlikely to be laying at this time so she doesn't need the extra calcium. I would also mix some scrambled egg into it and the Nutri Drench. Make her as comfortable as you can and keep your fingers crossed. If this is Marek's she will actively be shedding the virus whilst she is symptomatic, so take precautions not to transfer infected material to your other birds. I have not had one as incapacitated as that recover from an outbreak but that doesn't mean it can't happen. I would guess the main risk is that she will aspirate due to being unable to keep her head and body in the correct position.
I wish you luck with her and will be keeping my fingers crossed.
The best that I can suggest is to keep her well fed. I would give her a warm wet mash made with chick crumb rather than layer feed because it has higher protein and less calcium and she is unlikely to be laying at this time so she doesn't need the extra calcium. I would also mix some scrambled egg into it and the Nutri Drench. Make her as comfortable as you can and keep your fingers crossed. If this is Marek's she will actively be shedding the virus whilst she is symptomatic, so take precautions not to transfer infected material to your other birds. I have not had one as incapacitated as that recover from an outbreak but that doesn't mean it can't happen. I would guess the main risk is that she will aspirate due to being unable to keep her head and body in the correct position.
I wish you luck with her and will be keeping my fingers crossed.
