I believe that the best way to create good living conditions for any animal, whether it's a captive animal living in a zoo, a farm animal or a pet, is to base animal welfare programs on the core emotion systems in the brain. My theory is that the environment animals live in should activate their positive emotions as much as possible, and not activate their negative emotions any more than necessary. If we get the animal's emotions rights, we will have fewer problem behaviors... All animals and people have the same core emotion systems in the brain.
Temple Grandin, Catherine Johnson (2010). “Animals Make Us Human: Creating the Best Life for Animals”, p.3, Houghton Mifflin Harcourt