What you guys are talking about sounds a lot like a condition called Limberneck, Crookneck, Stargazing or Twirling, depending on who you talk to. It can be caused by moldy feed or an injury to the head, which causes swelling in the brain. This interferes with the bird's ability to balance. This condition is marked by the 'drunken stagger' (kinda like people being dizzy), the bird suddenly starting to walk backwards but not forwards, falling over, dragging it's head on the ground, the bird twisting it's head backwards and looking up, etc. Often they can't eat or drink because they can't target well enough to peck. Silkies, Polish and other crested breeds are especially vulnerable since they have that hole in their skull through which their brains protrude, and when another chicken pecks them on the head their brain swells. If it is due to moldy feed of course, you have to toss the old feed and get new.
I've got more on it here on my chicken site, including a link on how to dose these birds with the Vitamin E/Selenium combination:
http://jackshenhouse.com/VSChickHealth.htm
Scroll down to 'Crested Breeds' and click the link to Dr. Stanford's page--make sure you read both the article there called 'Crookneck Treatment' and 'Silkie Skull' to really understand it. I've used the Selenium/Vitamin E treatment (I had no access to Prednisone, a prescription drug, so I did without it) on adults and chicks alike that I thought were goners, and they completely recovered.
You have to be sure they are getting enough to eat & drink until they recover, if they are so bad that they cannot eat on their own, and I'd isolate them from other chickens so they don't get more pecks to the head & aggravate the problem.
To dose the bird I just crush the amount of Selenium I need to a fine powder. Then I take a vitamin E capsule and use a pin to poke a hole in one end, squeezing out the oil onto a small dish. I use a wooden matchstick end to mix the selenium powder into the oil (it will be gritty), then use the matchstick to feed the mixture to the bird--I open their beak and wipe it on their tongue, allowing them to swallow on their own.