The story jumps back and forth between the two and never distinguishes between them. The realistic elements include Toni's actions. He shows how dogs spend their days lying under a tree and eating all day. Another realistic element depends on how one accepted the events that happened within the two parallel days. If the girls were not actually turned in to dogs but were just pretending, then this fact is another realistic element.
Children often pretend they are animals, expecially dogs.
These quotes explain why one might think that this story is magical realism due to the two different worlds that are going on at the same time. The characters in this story did not hesitate. As a matter of fact, they did not hesitate when the children were turned into dogs and could speak. The reader does hesitate quite a bit. There is no hesitation between the author and the events.