1 Spanners: Eureka! I've invented a devolvo-gun!
1 Iki Piki: Cool! What does it do?
2 Spanners: It rearranges the molecular structure of a living being to show us what sort of thing it evolved from.
3 Spanners: Let's try it on that parrot.
3 Iki Piki: Uh...
4 Allosaurus: RAAARRRHH!!!
4 Iki Piki: Remind me to give you a lesson in Terran phylogenetics sometime...

2012-01-06 Rerun commentary: Parrots did not really evolve from Allosauruses in particular, but they did evolve from fairly closely related theropod dinosaurs. In fact there's a fairly good line of semantic argument, supported by lots of wonderful new fossils uncovered in the last 20 years or so, that birds are theropod dinosaurs.

Certainly we now know that many species of dinosaurs had feathers. Tyrannosaurus is a very late period theropod, and some fossils show skin features consistent with feather attachment points, although no Tyrannosaurus fossil has been found with actual feathers associated with it, and there are good arguments from comparative anatomy that this particular famous dinosaur didn't have feathers. But many smaller cousins of Tyrannosaurus certainly did have feathers.

Allosaurus is a much earlier dinosaur, that existed 90 million years earlier than Tyrannosaurus. (I've said it before, but it's so mind blowing that I'll say it again: Tyrannosaurus existed closer in time to humans than it did to Allosaurus.) Allosaurus existed at roughly the same time period as Epidexipteryx, currently the earliest known feathered dinosaur, which was in a different branch of the theropods than Allosaurus. It's unlikely that Allosaurus had feathers, and it's certain that Allosaurus is not a direct ancestor of birds. Epidexipteryx, however, might be.