Chickens tend to get along OK if you don't cram them in where they have no room to move. They actually make for quite affectionate companions if socialized properly. Nurture plays a huge role in animal behavior as well, and usually animals (including humans) simply tend to lash out when their needs aren't being met.

If you spend some time looking into modern animal cognition research, you'll notice the line around sapience is a very blurry one, with many animals routinely demonstrating that they are capable of complex spatial reasoning, theory of mind, and other traits we used to think only humans were capable of.

Also, you'll find plenty of humans are quite terrible creatures as well. That doesn't mean we can treat them indiscriminately. The capacity to suffer only requires sentience.

Anyways, I didn't come here to argue. Just to share my experience.