Wry neck can be a neurological symptom of head injury (silkie can be prone because some have vaulted skulls,) vitamin defiency, and from brain inflammation due to certain diseases. These links may be helpful as well as giving vitamin B1 or thiamine, vitamin E, and selenium. Selenium is found in eggs, canned tuna, and sunflower seeds. The first link to read below has vitamin dosages:
http://www.browneggblueegg.com/Article/Crookneck/Crookneck.html
http://oureggbasket.blogspot.com/2013/04/wry-neck-or-crook-neck-understanding-it.html
https://www.backyardchickens.com/t/97121/lets-talk-wry-neck-crook-neck
http://www.browneggblueegg.com/Article/Crookneck/Crookneck.html
http://oureggbasket.blogspot.com/2013/04/wry-neck-or-crook-neck-understanding-it.html
https://www.backyardchickens.com/t/97121/lets-talk-wry-neck-crook-neck