To be perfectly honest, I have no idea what is going on with this chick.
Monday i noticed it was sitting down a lot with its front legs sticking out and not strong enough to stand (there is a post on that, i don't want to duplicate). So i put it on vitamins/st john's worth/turmeric. I thought it was neurological or marek's (my entire flock vaccinated, and this would be the first bird to get it; unless the hatchery didn't vaccinate her!). all the other chicks are well. There were no obvious signs of worms or cocci. She does have decreased appetite, and she finds it hard to move around, when she tries to stand, first she stumbles a few steps backwards, then starts going forward. But when she just stands, she falls down on her butt, feet in front. Poop tested positive for both cocci and roundworms, and she just completed the first 24 hours of corid. I am also in two mind about what i should have treated first. Given there are no visible worms in poops, cocci sounded worst.
I stopped giving the save-a-chick and the vitamin b as i read somewhere thiamin can interfere negatively with the corid. I am giving her yogurt, mashed feed and water, some tinned cat food, some shredded fruit. She will eat baby cake on her own, and the cat food, but not enough.
I am giving her one more week to see if she shows improvement. I found a vet that can put her down, and send the body for a necropsy if we get to that point (which seems more and more likely to me!).
thanks for the replies!