This little chick has been totally fine and healthy and suddenly today starting bending her neck waaaaaaaay under her body and falling over. At first I thought it was because I put her in the bright sunlight, but I just looked and she did it again in her brooder tonight. Is this crookneck? Is there anything I can do? If I give vitamins to her for it as I"ve read her on BYC, can I give it to all of them or do I need to separate her? How is this caused? Any advice would be much appreciated. Thank you!