How much does she weigh? I would give her 1/4 ml per pound of SafeGuard. Then repeat it in 10 days. For the more rare capillary worm, you can instead five it for 5 consecutive days.
I disagree..capillary worms are not rare they are quite common. As far as getting a necropsy done ...results Can be inconclusive for Mareks. Personally I wouldn't waste my time or money with it unless you have another bird become ill.
Capillary worms can be destructive and deadly, and I would recommend 1/4 ml of SafeGuard per pound for 5 days. @ casportpony has dosages I am sure from Plumbs. There are studies that show repeated dosages will kill a higher percentage of worms.
Thanks all for the help but we eased her along the way Saturday. Nothing I was doing made her any better.
So sorry for your loss. If it makes you feel any better, chickens with neuro issues are extremely difficult to treat. Although it's possible sometimes to save them, most of the time it doesn't work You made the right decision.