and it appears to be looking up at the sky?
i think it does that because it is very scared
they keep their heads held high so everyone who sees them knows that they died with dignity.
I think that refers to the term: Deer in the headlights It probably saw the light, looked up, and then got knocked out so that it's neck was still craned up when it was dead.
I think critterman is the only one here that using any sense. Since the animal's neck is relatively long I think it's more than likely that it will be in an abnormal position after being struck. It's also possible, but I don't know for sure that the neck muscles that draw the head back are stronger than those necessary to allow it to lower.
It isn't craned back, it is in whatever position it ends up in after the deer is killed by the careless driver.