I know a bit how to use 3rd conditional, but not quite.
Situation: You suddenly heard sound from the lower ground of your house, which made you nervous about a burglar might be sneaking into your house. You almost forgot that you have got not-so-friendly dogs that bark when they see strangers. And you said:
Nah, my dogs would have already barked, if it really had been a burglar.
Is this correctly constructed? Because I've included the "be verb" specifically "been" in the sentence.
P.S.: The sentence above is a hypothetical thinking about a past event.