My wife and I purchased 21, six-week-old mixed breed bantam hens and roosters in May. One of the chickens started to wobble when it walked. One of its wings hung low and limp. Eventually the hen had trouble standing and finally it could not stand at all. Fearing a disease, I put the hen down. A couple of weeks later a second hen started behaving the same way and I put that hen down as well. It has been about a month since the last episode, but we have a third chicken starting the same behavior. At first we though Merak's Disease, but the chickens were supposedly vaccinated for this by the seller. A friend thinks it might be a contagious parasite affecting the brain and with no cure, the bird would have to be destroyed. Does anyone have any ideas what might cause this and if there is any other treatment other than destroying the animal?