If this chick was able to hatch on its own, its abilities are better then you might think. Thus, I would give it the chance to live.
Also...I think there are two things that can go wrong in the shell, of course we'll never be able to know what has gone wrong...if a chick hatches a 'stargazer' due to genetic issues, that's one thing. If a chick hatches a stargazer because of an unfortunate fluke of a bad turn in the egg one day, that's another thing.
If you sleep on your arm funny and it gets weird with pins and needles, is that a genetic mistake? No. It's a misfortune of bad positioning. I think some of the mistakes in eggs are NOT due to bad genetics, but simply bad luck. I would not condemn this chick simply because he put his head in a bad place and it got stuck there. Hatched with a kink in his neck.
For 'flippers', chicks that tip their heads backwards and then flip onto their back, I have propped them up in a coffee cup, in a standing position, for several hours at a time. They can't flip if they're propped upright. Sometimes this helps them get sorted out. If yours flips himself over backwards, the coffee cup trick might help.