Dan those hackles are Whiting "Flatwing" saddles-- a new product similar to their "Eurohackle" saddles. These are a new product for Whiting and they run 20 bucks for Bronze (feathers 10-13" long) and 35 for Silver (longer feathers). I find that the bronze saddles are fine for most of the patterns i tie.
You can find them in a bunch of shops- including here (I use them a lot and they offer free shipping): Whiting Flat Wing Saddles - Welcome to Whitewaterflies.com : The place for all of your fly tying and fly fishing needs
These type of hackles are used a lot here in the Northeast for tying flatwing streamers for stripers and tuna. The advantage is that you can imitate big bait like 16" herring and menhaden as well as smaller stuff like 3" sandeels.
I thought a flatwing might be a good one for musky since you can fish them slowly or even just swing them in current and they tend to suspend in the water column especailly with hollow tied bucktail. They also have a ton of action and can imitate a big meal.
There are a couple specific construction techniques to building flatwings, and here is a good step by step from Kenny Abrames' excellent site Striper Moon
East Coast Ghost
I'll be tying up a bunch of these style flies over the next week or so to get ready for striper season here and I'll post some pics.