My 4 week.old chick has strange behavior

My Easter Egger chick is acting so strange. She is burying her head under her stomach and is backing up her rear into a corner or against the feeder. I can't tell if her neck is hurt maybe? She is the only one who is doing this

Does she then go to sleep? She may have just figured out a way not to fall over.

It could be wry neck. Usually treatment is with vitamins (especially B1, E, and Selenium.) Poultry Cell and Poultry Nutri-drench contain vitamins and selenium, you can also try Poly Vi Sol baby vitamins (No Iron) 3 drops by mouth, and add some selenium--25 micrograms daily. Here is some info on wry/crook neck:

https://www.backyardchickens.com/t/858708/baby-chick-tucking-head-walking-backwards-and-flipping
http://www.raising-happy-chickens.com/wry-neck.html
http://www.browneggblueegg.com/Article/Crookneck/Crookneck.html
https://www.backyardchickens.com/t/97121/lets-talk-wry-neck-crook-neck

I've had enough wry neck in my flock to recognize it when I see it. yes she has wry neck. you will want to treat with be poultry vitamins, polyvisol without iron, selenium small amount ( large amount is toxic) vitamin E. some also add prednisone to this mix. for Exact doses and instructions go to browneggblueegg.com look up crook neck. He refers to Silkies specifically in the article but his treatment is the SAME for other breeds. By following his treatment plan EXACTLY I was able to completely cure three of my wry neck cases. my birds were severe. they couldn't eat or drink by themselves I had to help. they couldn't walk and we're doing flips. This treatment takes patience. it took about a full MONTH of treatment before mine in all cases were cured. I do believe in this treatment it worked wonderfully for me. Do remember wry neck itself is NOT a disease but a SYMPTOM of a under lieing issue. The issue could be vitamin defiency, or brain swelling from being pecked or just genetic predisposition. if it's defiency the vitamins help if it's brain swelling the prednisone helps , genetics is tricky. it can return after being cured if that's the cause but something is causing the wry . you should have success if you follow his treatment plan. not over night but in about 4 weeks. separate her and begin treatment ASAP hope this helps. best wishes

Oh no! Where can I buy selenium? My tractor supply doesn't have it

Pharmacy in the supplements aisle.