I could keep these little dinosaurs as pets, with no other objective or purpose besides admiring them because they are pretty to look at and that would not prevent any of the behaviors I listed.

What I’m about to say may evade you but cruelty is not an exclusive trait to human beings and chicken are a good example of it. They can be extremely cruel towards their own kind just for the sake of it. Not out of scarcity of food or living space. Just because they want to make another animal miserable.