What if Zootopia/Zootropolis should’ve include other animals other than mammals?

It’s known to be a mystery regarding Disney’s 2016 animated film Zootopia, or also known as Zootropolis if for those of you live in Europe, only features mammals, while they aren’t anything else, like birds, reptiles, amphibians, and invertebrates, since they’re all animals as well, if you saw the movie. So this theory can make you imagine if that movie include those.

Changes
TBD