I have this idea that furry avians should be slender and light, because that's how birds are in order to fly. Aerodynamics and weight and all that.
And then comes Razz with the big busty pigeon witch shattering that image like a wrecking ball...

... and now I have another image in my head which is Razz doing the wrecking ball video clip... I hate it here.

Ahahaha! Tiny green rat just hanging on the chain, screaming, as it swings back and forth. XD

I rather agree with you about how avian anthros Should look to be practical. But furries are, in truth, just fancy humans, and some humans like things Big. :D In my defense, I did not design this character (if I had, you can bet that bust would not be so unrealistically buoyant :D) but she looked like she would be fun and fairly quick to draw, which she was. :) Maybe all that extra mass is hollow like bird bones, or she's like a very top heavy emu and doesn't fly. XD

Fair.