If you do use the quill (whether goose or turkey or whatever) you can trim off the "feathery" part, since that's useless, except perhaps as decoration that might get in your way. But you definitely want to pluck with the stronger end--the end that was attached to the bird.

Jean Ritchie and all the other dulcimer people also talk about trimming a piece of plastic from a plastic container. You can use anything from a margarine tub to a bleach bottle, and the thickness and firmness of the piece of plastic will vary depending on your original source. Experiment until you get a pick you like, just like when you purchase a commercial pick from a music store.