SLOW Head "jerk" (more like pulling)

[lifthiminsong]

1-2 days ago, I noticed one of my RIR 2.5 yr old hens was moving a bit more slowly than usual. Still doing the normal chicken activities, but in slower fashion. She's been eating, but not with excitement, and she put herself to bed a bit earlier last night.
This morning she came out with the other girls, but glanced at the feed and walked slowly past it to be alone (not hiding though).

What I also noticed this morning is that she, from time to time, will pull her head and tilt it. She's not really "jerking" it, but pulling it sideways. I did NOT notice her gaping her mouth any.

Her stand and feathers are beautiful - I don't suspect parasites.

Any ideas? Sour crop?

Thanks!

 

[Eggcessive]

Do you know what wry neck or torticolis is, where the neck is twisted to the side, up, or downward? Could it be that? You can check the crop for being full and hard, or full and balloon-like, and check it in early morning to make sure that it is emptying. Here is a couple of links on wry neck:
http://oureggbasket.blogspot.com/2013/04/wry-neck-or-crook-neck-understanding-it.html
http://www.browneggblueegg.com/Article/Crookneck/Crookneck.html