I've seen videos of people doing it so I know it's possible, but I don't want to use bones on every single feather. I've searched around and experimented for hours now and I just can't figure it out. I've tried soft bodies and cloth physics but that doesn't seem to work with feathers. I want it to obey physics as well. If I animate the wing flapping down the feathers should curve back and vice versa, and of course the feather has to stay attached to the limb. I hope this makes sense.
blender physics likes simple shapes, you can get around this by using mesh deform modifiers, and surrounding the mesh you want to deform with a simple shape. For a feather, something like a 4 segmented rectangle around each feather. Then apply soft body or cloth physics to the rectangle.