I got a bit of a kick out of people speaking about animal rights. This, for more than one reasons but especially as homo sapiens are animals.
I would also like to clarify the notion that animals are not capable of true thought. This was a popular notion that has since been proven incorrect in various experiments, most notably the Koko experiment and further in other experiments with primates and cetaceans.
Finally, I would like to point out that the notion of "rights" is a purely man-made concept, just as "right" and "wrong" are man-made concepts. As a man-made concept they can be applied witheld to any creature on the planet.
As for bestiality - go for it, so long as you are not being cruel or forcing it upon the animal.