From a Buddhist perspective, it seems to me the tricky part of this question is not "animals," but "rights." The concept of rights developed in western civilization over many centuries and came to fruition during the 17th century or so, in the work of Enlightenment philosophers such as John Locke. But there was no such concept in the world 25 centuries ago, during the time of the Buddha.
Animal Rights and Buddhism
From a Buddhist perspective, it seems to me the tricky part of this question is not "animals," but "rights." The concept of rights developed in western civilization over many centuries and came to fruition during the 17th century or so, in the work of Enlightenment philosophers such as John Locke. But there was no such concept in the world 25 centuries ago, during the time of the Buddha.
International Chairman's Office 
生存乃是不斷地在內心與靈魂交戰；寫作是坐著審判自己。......................................................................