The architecture of the scene, like I said, is interesting in itself, but it does not prove 6 denials.
The first crowing was, most likely not heard by everyone. That Mark records it, and the prophecy of it, from the words of Peter, does not alter the number of denials, since St. Mark also records three accusations and three denials, like all other evangelists. All it does is possibly puts some time between the first denial and the second one, but even that cannot be asserted firmly because, in a populous city, we cannot assume it was the same rooster.
Maybe there were more roosters than just one.