Feelings and thoughts and actions aren't the same thing. This is really important to remember in so many parts of sex and sexuality, and this is one of those.
Is this a common way to feel? It's not, to the best of my understanding. But something not being common doesn't mean it's wrong. How you feel usually isn't something you can change, and with things like this, often trying to change feelings only makes them dig in more. Your feelings and thoughts don't have any impact on anyone but you. They can't hurt anyone, animals included, when they are only thoughts or feelings, so I don't see any reason for you to feel bad about them.
Laws notwithstanding, where we'd get into very problematic territory is that animals can't give fully informed consent to things outside their abilities to understand, like human sexuality. But again, that's about actions, not thoughts and feelings. Make sense?
Never doubt that a small group of thoughtful, committed citizens can change the world. Indeed, it is the only thing that ever has. - Margaret Mead