Usually animals are living for happiness like us , but the thing is many people around world treat them as slaves. If you would take a sheep for eg , people rear its wool even when it needs it . In summer it mihgt be helpful for itself but in winter its time for it to use wool so it can live warmly . But people rear it.
Animals do have right to live in safety because they are not intruders and this world is not only people's but they are also part of it.
People do not understand and expect many things from animals to do for them. When animal does not want to do works they torture it which is again wrong.They are n'yt our slaves.