Just beware where you glean feathers. A few presidents ago, a woman was picking up moults at Cheyenne Mountain Zoo (they said go ahead) and made dreamcatchers with them, and sent one to the White House. It was made with bald eagle sheds and she ended up in real trouble. Even though she had honestly picked them up as discards.
99.99999% of what us mere mortals would pick up for feather moults will be normal mundane species... I don't see where moults/sheds are harming a creature, they have discarded it and we are recycling it, but. It depends on your take on the source, indeed it does. In the 1970's, hair styles went from long to short, and someone that had access to lots of that cutoff recycled that into rope! Human hair rope for cattle roping. It flexed well, had enough stiffness for a good throw and apparently worked wonderfully (their grandfather had made same of horse/mule tail and mane hair, so that is where he got the idea). Is it wrong to recycle your own sheds?
I also know people that own/are owned by: wolves, wolf-hybreds, malamutes, huskies, etc; and in spring these creatures will 'blow their coat' and you get an incredible amount of shed hair. (we had a keeshond, same sort of coat, and we could fill a 13 gallon kitchen trash can over a few days as her coat came off). Some mix it about half with wool and spin a yarn and make sweaters (gorgeous natural colorings) and one said you could spin the wolf and huskie straight if you were careful. Is it okay to recycle your pet's hair? (I don't know how many things I've knit and crocheted and had my housepurrs contribute to it majorly as I went).....
I raised White Bantam Cochins specifically for their small white feathers to use in bird replicas (my primary income is from making animal replicas and costumes). Feathers can be clipped from living birds without harm.
Oops, upon consideration I realised my post may be off-topic since you're speaking specifically of materials naturally shed by the animal, not just materials which can be "borrowed" without harm...
The issue with Bald Eagle feathers isn't ethical, it's a matter of enforcement convenience. When Bald Eagles were seriously endangered in the Lower 48 (they've always been fine in Alaska) people shooting them for the feathers was one of the many pressures the population was under. Thus the Bald Eagle Protection Act made mere possession of the feathers illegal, not because harvesting dropped feathers harmed the birds (although it might, if people came trouping past their nests everyday looking for more dropped feathers) but because it was too easy for a defendant to say "I didn't shoot any birds, I picked up these feathers in the woods, find a body or shut up".
I personally cannot imagine any ethical issues with making use of dropped feathers or furs that a wild animal is not using any more. Likewise antler, which is a big deal in moose country; a shed antler from a moose has many excellent uses for artwork and tool making.
I did some manufacturing work for a Native American during my stint in urbania about 15 years ago, and they had a few bald eagle feathers. They were turned over to me with paperwork as the person was legally allowed to have some. I manufactured the item from wood, deerskin, sinew, beads, and some parts of those feathers and gave it all back, all snippets of feathers included in a baggie. Just a point out that a few things can be trouble, and best not to go there. <smile>
A few places antlers are restricted too, depending on what they came from. Just doublecheck before gathering those. (I've sawed many a legal deer antler for knife handles and jewelry, that's a stinky dirty job, but.)
That said, I don't see where castoffs and sheds are hurting anything. But it's still up to the person collecting and using, on if they think they should, if they think they could, and what it is used for.
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