Of course that is a good question, although I would expect that with the most useful or most reasonable or best definition (which is itself not entirely clear, though), that the answer will probably be, yes, animals are conscious (although not always all the time; unconsciousness and partial consciousness can occur too).

Scientific experiments can detect specific things and specific details (if tested in an appropriate way), but this would be something specific rather than just being called "consciousness", is what I should think.