thanks, all, for the responses. Much appreciated. From what I've found from additional searches this morning, at least one way is to mix up squirrel hair (NOT tail hairs - they're too long) as a dub (i.e. coffee grinder), and then use a dubbing loop.
In reference to the Petitjean Magic tool, that seems to be appropriate for feathers (with stem), where you can jam that stem down into the tool, and then grab the barbs with a clip.