Thanks @casportpony.
I am stunned how fast this took her. 3-4 days from first limp. I kept hoping I would go out and find her even slightly improved but she just kept getting weaker. They were on day 5 of their coccidia treatment today. I hoped maybe it was worm load. It wasn't. This is really the first bird that I have lost with classic Marek's symptoms. Pullet under 6 months with sudden paralysis and sharp decline. The others who died presented with weird symptoms or died suddenly. My other bantams are so far so good.

But I'm being realistic. I know it isn't the end of this disease's attack on my birds. I'm just hoping for a lull at least. I have two broody hens and bringing chicks into uncontaminated surroundings is next to impossible. If I had a lot of chicks to hatch I would probably vaccinate but once again, I don't have any place on our farm that I can consider clean for any chick hatched by a broody to have a fighting chance of building up immunity.
I'm hoping these little ones have inherited a modicum of resistance from the hens that laid the eggs. Both of them are OEGBs, 8 months old and so far healthy. They were neighbor eggs, broody hatched.