Amazing! Got a rare Shetland breed for the first time this year. One chick suddenly lost control of his legs and couldn't stand. We thought he was a goner. I had to attend to him every 15 minutes in the brooder to hold him upright so he could eat and drink. Got hold of my avian vet who prescribed Amoxicillin. For 48 hours no signs of recovery, but chick was still lively and eating and drinking when held upright. After this period he started to spend less time on his back and even try to move around on his tummy. Third day he was walking, but unsteady. Fourth day, he was back to normal. I couldn't have believed that such a loss of muscle control was simply due to an infection of the brain. He would have died except for the expertise of my vet. Now he is 3 months old and fit as a fiddle! If any of you have had this problem, don't write them off! It is not necessarily Marek's disease.