Update: both chickens have now passed away, one naturally and one had to be put down. We still don't know what caused it and are curious to find out to prevent it from happening again.
About a month ago, I posted about a chick that suddenly could not walk and flopped around. Some helpful folks and research convinced us that is was vitamin deficiency. However after giving it polyvisol (w/o iron) and vitamin E with selenium, it hasn't really improved. It actually has begun to go...