My 8 week old chicken seems to have a crooked neck. She lies her head on the floor and drags it as she walks backwards. This is at night or in the coop. While during the day and in the run she has only a sideways tilted head and has good balance. No other symptoms yet and the three other chickens seem fine. Has anyone any ideas? I've found some information on Polyneuritis which is a vitamin B deficiency which might explain the symptoms. I do not think any other sort of injury has occured, but you never know. Thanks in advance.