Poor Mexico! First swine flu, then an earthquake, and now they aren't responsible for the extinction of the dinosaurs! These big, stupid, flightless birds did not die off with this asteroid hit. In fact, it had no impact! (ha, ha!).
The dinosaurs were just a big evolutionary dead end, brought about by the massive warming caused by the continents all being squished together. When they separated, these birds were doomed. It might have been the Deccan Traps that finished them off, but had they been happy, they would have repopulated. As it was, the smarter animals rose up. So, even if you suddenly hatched a magic dinosaur egg today, the mosquitoes would kill it!