Short answers, pulled from the story.
The down feather lacks interlocking barbules found in pennaceous feathers, making it soft and fluffy. It has a short or vestigial rachis with few barbs and barbules that lack hooks entirely.
Specimens discovered in western France, Canada, and northeastern China suggest non-avian dinosaurs possessed down-like structures before modern birds evolved. These fossils indicate some species had primitive forms of insulation at an earlier origin than previously documented.
Indigenous North Americans use eagle down for religious ceremonies as powerful symbols within traditions like the Ghost Dance movement. Zuni prayer sticks utilize eagle down in their construction while Hopi people rub eagle down over rattlesnakes collected for Snake Dances to soothe reptiles.
Approximately seventy percent of the annual harvest originates from Iceland alone where communities have protected eider duck nests since 1890. No more than four tonnes of eiderdown comes from wild nests each year globally with fifty to sixty nests producing about one kilogram of down feathers annually.
Live-plucking remains illegal in Canada, the United States, and Europe yet occurs in Poland, Hungary, and China according to industry reports. Public sentiment against the practice has been strong leading companies like IKEA and Patagonia to alter product lines to eliminate use of live-plucked down.