I think birb wings DO curve in the way that I think you were going for - they can do a lot of weird aerodynamic stuff that airplane wings can't - but there is still usually kind of a bulb-y mass along the proximal leading edge since there's some chicken muscle there (<--- did advanced biomechanics in university... it was a lot of fun looking at various approaches to the same problem in the animal kingdom). That's where I cheat.
Also that reminds me, I saw baby geese today and they were so adorbs. They had no feathers yet, only fluff, so when they flap their itty bitty nubby wings you can see all of those muscles, haha.