
Hi! Guidelines by the FCC in this country say that for a product to be advertised as "Down" it should contain at least 80% Down. 20% by products such as small feathers, crushed feathers etc, deemed acceptable.
Down is of varying quality. The premier Down in the world is Eiderdown from the sea dwelling duck of the same name. This is now a protected species so products from this duck are rare indeed.
Next in line is Goose down and then duck down. They are both very good and durable and rate pretty close in quality. You do get what you pay for. Good Down is expensive.
Feathers do vary depending on what part of the body they come from. Naturally, the smaller and softer the feather, the better, if you go for that sort of thing. Also, it's important that the down or feathers come from a lean, mature bird. If the bird is fat...the product will have a strong odor.
Some places in the world raise geese for just their down. These geese are plucked live(South Africa being an example). In the rest of the world, it depends on what countries consume the most ducks and geese for their food supply. These are the areas that produce the bulk of the worlds Down.
On the old feather pillow you have....do some study on dust mites..chances are the weight of that old pillow is mostly made up of these creatures. You can get "dust mite free" or "dust mite proof" covers for new pillows and comforters these days and you can purchase feather pillows that have been treated so no dust mites invade..but I'd worry about an old one. Blech!
Hope this answers a couple of questions. Happy Spring!!! LQ