Thanks to one of the members on here I have gotten the urge to want to make some of my own fletchings from turkey feathers

Will dying the feathers mess up the natural waterproofness and oil already present

No they should fold and clump together as they do when not dyed... lol You can always spray them with food grade silicone.

To get the dye to set in well you usually have to wash out the oil so I'd say that it does take away the natural waterproofness.
Denny

I don't wash my feathers. Just soak in warm water with a little dawn soap and vinager then warm water and vinegar then dye them. They take color well and are much more water resistant than comercial feathers. More durable as well. If I go natural color I use a white fur tracer. Looks cool and works great.