Gadwall is one of my favorite feathers to use as spey hackle for steelhead flies. Unfortunately if you want it in any color other than natural it get's pricey. I had heard rumors of dying feathers with Kool-aid and decided to give it a try one day, I'm pretty happy with the results.
After doing a little research I found out that Kool-aid works as an Acid dye so it should work well with all protein based materials like feathers and hair.
You need three bowls to dye a batch of feathers.
I fill the first bowl with warm water and some liquid dish soap. I wash the feathers in this bowl to remove any grease or dirt from the feathers.
After the feathers are washed I move them to a second bowl to soak. The second bowl is water and Vinegar. I dont measure but I would guess I used about 1/3 cup of vinegar. Then let the feathers or hair soak for around 5 min. The vinegar helps the dye soak in and set so it does not wash out while fishing.
After the feathers have soaked I move them to the third and final bowl. This bowl has two packets of Kool-aid, water, and a little bit of vinegar in it. I make sure the feathers are submerged and put the bowl in the microwave for 2 minutes, let it set for a couple minutes and microwave it for two more minutes. The dye absorbs best while the liquid is hot.
If the feathers are not as bright as you want, let it stand a little longer or give it another shot in the microwave. .It doesn't mater how much water you use, The water actually gets clearer the longer the materials are in it.
Rinse the feathers well, until the rinse water run's clear and then a little longer. Make sure you get all the excess dye off. let the feathers dry and then your good to go.
Here are a couple I have tied with Kool-aid dyed feathers.
This first fly has a dyed hackle and the second has blue dyed cheeks and the red body veiling.