Two days ago, I noticed my 1yr old Barnevelder walking oddly on her right foot, toes curled under, occasionally using her wing for balance. In all other respects, she was behaving normally--eating, drinking, pooping well. Later that afternoon, I noticed she would at times stagger and fall to one side, with her right foot curled under her and later, fall in such a way that she had both feet curled up and raised (see images). At that time, I immediately isolated her. She was extremely passive on Saturday, but all bodily functions seemed normal. I checked for injury, bumblefoot, pain in the leg or foot and found nothing. I gave her some electrolytes in water for a boost. My initial gut response was onset Marek's, but she did not have and has never shown the classic posture and is able to grip my fingers with her feet when I hold her. She has good leg and foot resistance. Yesterday was worse, then today, better--but the presentation is odd. She is normally a wary bird and not that social and today she had her normal uppity resistance to being held. She ran from me! There are times, however, that 1) she walks on the knuckles of her right foot or 2) attempts to balance on her right foot to scratch with her left and falls over. When she falls over, she sometimes ends up on her side or back with both feet curled. She can right herself with difficulty, and sometimes walks away quite normally. And, as I mentioned, she ran from me a bit ago. Pictures here show her in various postures Saturday, including walking normally, walking on knuckles, sitting on hocks, and falling over. ( Wing strength is great. Eyes are clear and normal. Head bright, comb bright red, eating and drinking well, preening. I know there are plenty of things that can mimic Marek's--a vitamin b12 deficiency among them, but so much of what I read discusses this in chicks. I have given her two rounds of B12, one yesterday and one today. Any ideas here on other things to try?