Here's the info: 1) Cuckoo Marans chick, 10 weeks, I think she's lost weight in the last week - feels lighter than other chicks and she used to be the biggest. 2) She almost can't walk at all now. She sits most of the time, and often her legs stick forward instead of sitting up under her. When she does walk she is extremely unstable and usually only makes it a few steps and then falls. Last couple of days she even seems to have trouble sitting upright - uses her wings to steady herself. 3) I got back from a vacation 8 days ago and she had a "limp" when I got back and it has steadily declined since then. 4) My 3 other chicks are all doing spectacular, no signs at all. 5) No signs of trauma, legs look fine, no blood. 6) Nothing has changed in the environment. FYI, chicks were all vacc for Mareks. 7) She is eating and drinking, although today I don't think she could get to the water, so I moved her to her own enclosure with low food and water. She's eating a supplemented Chick Starter. 8) Her poop looks totally normal and is of a good consistency. 9) I've been giving 1/2 tablet Vit B supplement crushed in water via dropper twice a day, but it's hard to say exactly how much actually goes in her. 10 ) I hope to treat her myself, but would consult a vet if really necessary. 11) Bedding is white shavings, as rec by breeder. Sprinkled DE underneath. I'm hoping to find a dose for the Vit B and the best method of delivery, since she doesn't enjoy the dropper and I'm not sure it's really efficient. And of course, if you think it's not Vit B, please post ideas!!