I can say that in CA cats are considered free range animals, as they can jump over any fence. Dogs are, however, required to be on a leash when out of their own yard, and if they attack another animal, leashed or not, it is the dog's owner's responsibility. We had two cats injured bad enough for surgery, and two cats killed by dogs, all within 6 months. It happened at night, so we don't know which dog, but our cats are not allowed outside unsupervised any more. They stay in our yard anyway, but now we stay out with them, and they all come in before dark. Too many irresponsible dog owners out there. BTW, we also have dogs, and they are leased when out of the yard, and are behind a high fence that they cannot escape from. All are licensed and neutered. I know the difference between responsible and irresponsible pet ownership. I think the dog owner needs to be paying that vet bill.