I don't suppose there's much of a market for feathers now (as opposed to down). What were they all used for: mattresses? Golf balls?
Stuffing feather mattresses, pillows and cushions. Feather mattresses are still used today, but are not popular, having been displaced by spring and or foam types.
Feather pillows and duvets remain popular.
Down is often considered to be better, but is much more expensive. A basic feather pillow can be purchased for about £5 and is
IME▸ far superior to synthetic types. Can be composted when no longer serviceable, unlike synthetic materials.