For practice and strokeplay: plastic, actually nylon, as better ones just because its cheaper and you still get to practice. For games: clearly feathers since their flight and feels are very different. Ofcourse, good feather shuttles for practice tends to get expensive. read more
In a feather shuttlecock, the feathers are arranged in a conical shape and go into a cork base. Duck and goose feathers are used to make these shuttlecocks. Synthetic shuttlecocks, on the other hand, are made with plastic and have the same conical shape that you find in feathered shuttlecocks. read more