First get fluids in it, give fresh water every 20 minutes or so, you can alternate fresh water and electrolite water. If you don't have electrolites, then some sugar water. It could just be shipping stress, it takes a toll on some of them, they easily get dehydrated or chilled. Once it's hydrated then you can give some B complex (human ones) grind up and mix in some moistened feed, 1/4 tablet a day, and some vitamin E (with just a tiny sliver of selenium to help with uptake of the E), just poke a hole in the capsule and squeeze it, drip on the beak, it should swallow it. Being deficient in the B's can cause neurological symptoms and being deficient in E can cause wry neck, not uncommon, and deficiencies can come from the parent stock. Do you have a heat source for it so it can stay warm? If it's not moving around you will need to monitor so it doesn't get overheated or chilled since it may not be able to move in and out as needed. I have sometimes carried a weak chick in a neckerchief tied around my neck, like a hammock, so it rests against my upper chest, It can hear you talk, hum, sing etc, and it can comfort and calm them, and sometimes give them more will to live. Watch for pasty butt and take care of that right away, struggling chicks are more prone to it.
More on wry neck:
https://www.raising-happy-chickens.com/wry-neck.html
