Help with quill wings
 

I was trying to tie a fly created by Larry Coburn for the Gunpowder.
It's a version of a sulphur that has duck quills tied down in a wet-fly
manner. I don't use quills much and I know why. I tried 3 times and
they kept splitting on me. They look like crap! They might catch fish
but...

Does anyone have tips for tying with duck quills? I looked at the Desk
Reference but it didn't help me.

Thanks in advance.