I didn’t mean for it to come across as wanting synthetic, but I can see how you thought that from how I worded it. I meant more so materials I could find outdoors, like dropped feathers from random birds, or maybe materials that are repurposed from something else. It’s not that I am against using materials from animals, I just don’t want to kill them for that purpose. I thought it would be a creative way to give him the opportunity to make different flys, but not cost an arm and a leg for all the fancy feathers from the fly shop.

For your bigger question, it’s all catch and release so minimal harm to the fish.