I had an adult silkie chicken with what I think was wry neck. This was before I was on the BYC forum unfortunately. She had a hard time eating because of the neck twisting.
Here is a copy/paste:
Wry Neck (Crooked Neck)
A bent neck can be a genetic condition or can be the result of a vitamin deficiency. When it is the result of a genetic condition, there is no treatment. Some breeds, such as silkies, are more prone to getting it genetically. Vitamin treatment is still worth a try. If the wry neck is a result of vitamin deficiency, the vitamin treatment should clear it up.
Vitamin E gel caps with Selenium - give the chicken the liquid from the gel caps. Make sure to get the kind with Selenium for proper absorption.
Polyvisol without iron - this is a liquid vitamin supplement labeled for infants. Get it at the drug store or some grocery stores. Can be used in addition to vitamin E when treating wry neck.
A more comprehensive treatment:
First week:
Twice a day
2.5 mg of prednisone
400 IU of vitamin E
Once a day
A piece of human vitamin B complex pill or a squirt of human liquid vitamins
Selenium (50 micrograms/day for half size juvenile for 3 days)
For the second week:
Once a day
2.5 mg of prednisone
400 IU of vitamin E
A piece of human vitamin B complex pill or a squirt of human liquid vitamins
Every other day
Selenium (50 micrograms/day for half size juvenile for 3 days)
For the following weeks:
Once a day
2.5 mg of prednisone
400 IU of vitamin E
A piece of human vitamin B complex pill or a squirt of human liquid vitamins
Every third day
Selenium (50 micrograms/day for half size juvenile for 3 days)
Do not abruptly stop prednisone, the swelling rebounds, decrease dose gradually.
Vitamin E recovery can be slow; continue the vitamin E for several weeks at least.
I got this from a helpful link that addresses treatments for a variety of ailments:
https://www.backyardchickens.com/forum/viewtopic.php?pid=6580204