Well, it strikes me that a cataclysmic and radical alteration of the environment due to the impact is not inconsistent with some sort of resulting brain damage in the creatures killed.IIRC, lack of oxygen causes a similar posture in victims of near drowning.
A near global firestorm, followed by a couple months or years of darkness would surely drop oxygen levels. That would be consistent with both the impact and massive volcanism theories.
Or they could just be pining for the fjords...
The earliest feathered dinosaur, Archaeopteryx (plumage not shown). Drawn from specimen at Humboldt Museum, Berlin. The skull is about six inches long.
An ostrich-like dinosaur, Struthiomimus; in the classic posture indicative of brain damage and asphyxiation at death. Drawn from specimen at American Museum of Natural History. The skull is about a foot long.