Re: Wild Duck Feathers..
I have many friends that bring me their bird carcass so I can pull feathers. I bag them in like kinds and place them in the freezer until I decide to dye a batch, sometimes they stay in there a couple years before use.
Freezing for a month or so from my understanding is long enough.
"I've never missed a Steelhead by waiting too long. It's true, but I've missed plenty trying to set the hook too quickly." Dec Hogan 'A Passion For Steelhead'