I have had a few rats and a mouse with the head sideways thing. In the mouse it was caused by an ear infection and eventually he got better and went back to normal. The rats all had a seizure which left them with their head twisted, and one girl an extreme craving for meat? Anyway, so far in the cases I mentioned the rodents did not die, well except when I culled them. But those are a few other reasons they might have their head twisted, though not sure how helpful it is because this sounds quickly fatal.

A lady I know lost all but one of her mice and this is how she described it, they all died within 3 days. She never was able to find out what happened however, so not very helpful other then to know whatever it was was very contagious and killed quickly.

"One by one they came down wth some sort of horrible unidentifiable malady that put them into a severe torpor, then convulsions and death within hours of the original symptoms."

Sorry I'm not more helpful, good luck though!