I recently got 17 chicks that hatched may the 18th, and one of them, a Speckled Sussex, had crooked neck. At first it looked pretty bad, and i was worried, but ive been caring for it the same as the rest, and it has been healing up slowly. He is still a bit of a... strange one.... but he doesnt...
ok, i believe i might know the problem, but im not sure... try checking out this page, it talks about the same effects your chicken is showing
http://www.raising-chickens.org/chicken-crop.html