SpiderJerusalem: “People generally do not keep cows, chickens, sheep, or deer as pets.”
Probably because they are too big, and zoning laws don’t allow it,j and because it’s awkward eating one’s pet. However people do keep such animals, including chickens, as pets, and people who raise them see plenty of signs of personality.
The halachas on eating animals are not based on the personality of the animals, since if that was the case we’ld be vegans. It’s based on Torah. Ha-Shem said “eat” and we “eat”. If we encounter a new sort of animal, we don’t give it a personality test – we determine if it is a type of the critters we’ve been ordered to eat, and if it’s a match, it’s dinner.