Split the shaft into several sections. People used to make snares out of split shafts from some of the larger birds like swans. Look at a down feather with a hand lens. Try to smooth it down as you did the larger feather. Look at the shaft on a down feather.
Feathers are important in keeping birds warm.
People use down clothing and sleeping bags to keep out the cold. Ask the elders about using feathers for insulation. Experiment with the insulating quality of feathers. Then discuss why feathers are good insulation. Speculate as to which is the best insulation.