My father grew up with a few siblings, which he had varied relationships with. He never really got along with his sister, and they frequently fought. And, as it turned out, some of their pets shared those sentiments.
At one point, he had a pet bird, I think a budgie. He'd occasionally take the bird from its cage and let it fly around the house. Occasionally it would perch on his shoulder and nibble affectionately at him.
His sister also had a pet, a cat who was friendly to her, but disliked my father. The cat would frequently attack him and trying to make his life miserable. Coincidentally, when my father's bird was flying around, it would often poop on his sister, much to her displeasure.
