Ok this is a method I use on my 60 priest to farm for light feathers.

In westfall west of Moonbrook there is a graveyard where some birds are flying around.

If its daytime outside kill one, you'll see they instantly respawn.

These birds have a chance to drop feathers, greens, eggs, etc-but overall the feathers are what your after as you can sell stacks on the AH for a decent amount for the very low amount of work involved.

Light feathers are used by mages and priests to gain slowfall/levitate which is why they're desirable to farm, there's a large need for them