Well my EE that was suspected with meraks, got her lab work back, and nothing seems out of the ordinary the vet said, so we.both are not sure what's going on with her, she is submitting her case to Purdue and hoping for a reply, she is attempting to stand, but still can't yet, and from what I'm researching in my own I can't find anything similar to what she is displaying.
Here is my story of my ee pol pullet who one day just stopped walking. https://www.backyardchickens.com/t/741957/not-an-emergency-mareks-in-the-flock/380#post_11518874
I started her on vitamin b complex that I bought at Walmart, I also started her on the suggested flora-gen(I only had her on this for a short while) Had her on it (vit b complex) for I'm guessing 6 months. Today she is walking, running, pecking like normal. I stopped the vit b in December. I just added on crushed tablet to a waterer each day. Vit b is water soluble meaning they don't stay in the body long and need to be replaced. And if they don't need the vit b all extra is eliminated through their poo. So it won't hurt them any to get extra.
The people on that page, most do have mericks in their flock. They are very helpful and knowledgeable. They may be able to help you out. Even more so than a vet as they deal with md every day and Purdue and Texas A&M on a regular basis, and the vets normally don't.
I think my girl got into something. We had a chicken, who was killed by our dog, necropsied she was neg for md or any other illness. I have had no other illness since. Wait one, sour crop. Which is roaring it's ugly head again. Will probably just put her down.
Good luck with you girl, and check in with that other thread, they are wonderful people!!
Deb