So,
1)she is an EE, 6 months (21 weeks), but not laying yet- but neither are any of the other nine I got at the same time, I have no idea how much she weighs, but shes not overly fat or skinny.
2)she flicks her head over and over again. When I picked her up she stopped, but started again when I put her down. she has been doing it for at least 3 days. when I looked at her head I noticed some white sheath like things when I ruffled her feathers, kind of like dandruff but some still around the base of the feathers. I compared this to the other EE I have and she didn't have this.
3)no trauma
4)I think that the cause is the mystery here
5)she is eating and drinking normally. I took yogurt with flax meal to them this morning with a special little bowl for her, she didn't want it. she thought I was chasing her when i tried to single her out to give it to her. But she did go after the lettuce and apple scraps and of course the little bit of corn my daughters sprinkle out in the morning. I also saw her drink.
6)I have not been able to catch her pooping so I don't know what her poop looks like in particular, but I haven't seen any unusual poop on their poop shelf.
7)no treatment so far
8)I won't take my chickens to the vet but I will do anything I can do.
9)They have a secure coop they roost in at night with pine chips on the floor and a poop shelf below the roost. They have a large enclosed run they spend their time in the day in. Although there is a large bird flying over lately and they run inside whenever they see it. The run has a wire roof though, for just such an occasion, they just haven't figured that out yet.
I think that the dandruff is a corresponding symptom but i don't know of what. She is not coughing or sneezing and I see no discharge. It is really just the head shaking, and none of the other nine are doing it.