I’m no expert but they collect the feathers when the birds molt. As far as I know all birds molt. In any case, the feathers would have to be sustainably sourced as there is essentially no market for anything new with feathers that someone went out and shot a bird to get so nobody would bother to make anything from them as you can’t sell them.
Folding fan with representations of Pompeii and the 1786 Eruption of Vesuvius. ca. 1795. Gouache on parchment; Tortoiseshell sticks and guards with the leaf in gouache on parchment; gilt metal and glass decorations. Inscribed on the back. Collections of the Metropolitan Museum of Art. In the public domain due to age. https://www.metmuseum.org/art/collection/search/209815