I thought things like mirror tests don't work on cats, because they are such assholes they actively sabotage such experiments. For a time it was even thought cats were very dumb, but later tests have shown them to be actually very smart.
I heard a pet behaviorist explain the mirror test for roosters/chickens had to be designed with consideration for them being social animals. They found when putting a mirror without other chickens around, the roosters wouldn't crow when a predator was flying overhead. Yet, with other chickens there, they did
I guess so. Roosters are the ones that crow, but when they're alone (seeing themselves in the mirror) I suppose they figure they don't need to signal there's danger. I'd have to look for the video and paper for more details on whether they tested whether this was true with other roosters or just chickens, but from my memory I think they did both