This is way too easy.
I reduced the recipe from the one I had read cause I only had about 25-30 feathers left and wanted some red barred ones. Here's my solution.
1 1/2 cups water 2/3 cup white vinegar (probably could have done with less vinegar?)
Heat in microwave for 4 minutes, then stir in 1 packet of Cherry Kool aid. Put back in micrwave for 1 more minute while feathers have been floating in the kitchen sink in warm water and a couple drops of dawn dish liquid.
Removed from microwave, stir again and drop feathers in. No need to rinse them, I just shook the excess water off and into the Kool aid/vinegar solution. I left mine in there for about 15 minutes cause I wanted them nice and dark!
Here's the results.
The 3 solid ones on the right were bright yellow and I just threw those in to see what they would turn out like......bright red was the result.