Head shaking chicken!

I've only had chickens for a year so I'm hoping someone will tell me that this is just something they do occasionally!

I've got a hen, who is about 1 yr old, part Silkie. This morning I saw her do the head shaking thing for the 3rd time in the past month. She'll be standing somewhere, seemingly comfortable, not stressed or hot or scared. She gets a vacant stare and her head/neck swivel around about an inch repeatedly! Looks almost like a cartoon character doing an exagarated double-take.

She came to me last Aug with tattered looking feathers and may be molting now. Has laid soft shelled eggs off an on during the last 2 months, interspersed with normal laying for weeks at a time. All other indicators seem to be normal

Thanks for any help!

 

Appreciate the info folks.

Jarvxs, I'm pretty sure its not stuck food, as the rotation is robotic and rhythmic. No apparent attempts to cough or shake.

howfunky, they've been wormed, most recently with Wazine, followed by Fenbendazole and the environment is pretty clean. No external parasites visible.

Anianna, I just checked out the sites you recommended and have marked them for future use! Awesome and important stuff there. I then googled wry neck/crooked neck and watched a youtube vid of a silkie with wry neck. Gypsy's condition is nothing like that. When I bought her I was under the impression that they were being well taken care of..... now I know better. I slowly switched them all (got 4 from the same lady) to an organic 16% layer ration, supplemented with organic wheat/oats/millet (my girls won't eat corn at all ). They get organic hulled sunflower seeds and dried mealworms as treats. There is plenty of green stuff in the fenced pen area (much of it they won't eat) and they get out to free range our large fenced yard at least 2 - 3 hours every evening. We use no chemicals here, and have well water so no chlorine or fluoride. They get unsweetened yogurt every other day and ACV in the water 5 days a week.

What am I missing here? Thanks again!

 

Any other ideas, advice or suggestions? Please!