I think it a given that most living creatures have something besides an autonomous nervous system. They are all sentient to one degree or another. Parrots are smart. Chickens not so much. Predators and scavengers have no qualms about eating you so why should you forego nutrition in favor of herbivores or insectivores or fish which are almost all predators of one sort or another? I can't understand your rationale. Prey animals are sentient? And?