When I get feathers, I put them through a few freeze thaw cycles. I put them in the freezer for a week, then out for two, and repeat that 3 times. Then I store them in airtight tubs sprinkled heavily with borax. The cycles allow any eggs to hatch, then the freezing kills the larva. If the eggs are not allowed to hatch (the thaw cycle) the eggs will not die, just remain dormant. I detest bugs that eat feathers, its pretty much all out warfare on them. And like Osage Outlaw, I can't stand mothballs.
Kyle