Basal traits for avian evolution included four wings and feathers all over.

[Jura <pristichampsus@yahoo.com>]

Apologies for beating Ben Creisler to the punch here :), but this just came out 
today:


Hind Wings in Basal Birds and the Evolution of Leg Feathers

Abstract


Recent discoveries of large leg feathers in some theropods have 
implications for our understanding of the evolution of integumentary features 
on the avialan leg, and particularly of their relevance for the origin of 
avialan flight. Here we report 11 
basal avialan specimens that will greatly improve our 
knowledge of leg integumentary features among early birds. In 
particular, they provide solid evidence for the existence of enlarged leg 
feathers on a variety of basal birds, suggest that 
extensively scaled feet might have appeared secondarily at 
an early stage in ornithuromorph evolution, and demonstrate a 
distal-to-proximal reduction pattern for leg feathers in avialan 
evolution. 

http://www.sciencemag.org/content/339/6125/1309

Interesting side note: This hypothesis has been suggested (and supported) by 
Evo-Devo data since ~2003 (e.g., Roger Sawyer's work). It's cool to see that 
the fossils now appear to be backing it up.

Jason