"What about utilising a silver phase (assume you aren't wanting brown gene) Welsh Harlequin with a Dark Dusky Runner (if you have them)?"
Well, I thought about that, but untill very recently I didn't have any ducky runners, and the ones I DO have I think are 1/2 dusky (as per much of this previous thread) Seems like here (in the US) we have mostly the common colors: white, blue, black, and penciled. Some of the other colors are very hard to come by. That's part of the reason I'm breeding them. They're beautiful and unusual.
"I just went back & refreshed on what she (Silver looking duck) was bred out of. Blue Trout is Saxony less one dose of blue, correct? So theoretically & if birds genetically to text, Blue Trout x Saxony would produce approx 50% Blue Trout & 50% Saxony coloured/patterned progeny! Therefore, your duckling without blue, & the two silver looking birds would not have come from the Blue Trout x Saxony! The Blue trout was involved (as only drake), but so too must have been your white duck, for those three duckling @ least, if the Blue trout & Saxony are genetically correct."
I may not have mentiond this, but 3 of those ducklings (the grey, and the 2 blue fawn) came out of a different pen, one with only greys and blue fawns.
Anyway, you're probably right. Too many possible variables in my hens. I DO think that they came from the white hen because their body type is much more like hers then any of the saxony or trout runners. A little more stocky.... less "typy".
We'll see what comes of all of this. I've got a broody hen sitting on some of their eggs now. 4 weeks and counting!