To get Splash 100 % of the time you will need to breed Splash to Splash. To get Blue 100% of the time you can breed Splash to PURE Black, the reason I say PURE Black is because alot of Silkies that look black are actually Blue.
So here it the scoop on breeding Blues, Blacks and Splashes. Use the Parsons Square below
BB = Splash
Bb = Blue
bb = black
Breed BB x BB Splash to Splash = 100% Splash
B B
---------------
B BB BB
B BB BB
Breed BB X bb Splash to Black = 100% Blue
B B
---------------
b Bb Bb
b Bb Bb
Breed BB to Bb Splash to Blue = 50% Splash, 50% Blue
B B
-----------
B BB BB
b Bb Bb
Breed Bb to Bb Blue to Blue =25% Splash, 50% Blue, 25% Black
B b
-------------
B BB Bb
b Bb bb
Breed Bb to bb Blue to Black = 50% Blue 50% Black
B b
----------
b Bb bb
b Bb bb
And of course breed Black (bb) to Black (bb) = 100% Black. If you get anything other then Black when you breed them together means they were not True Blacks unless of course they both carried the resessive lavender gene then you could get lavneders.
So anyway, short story long that is how it works. Hope I did those right, don't want to make it clear as mud !! lol This is the simple version. Dont' ask me any more then that !! I"m lost, it gets alot more complicated when you start talking black alle(sp) ^ and a bunch of other weird things that can make a chicken look black but affect the outcome color. Genetics Ahhhh, wish I would have paid attention in HS !!! And whites, that's a whole different ball game !!
Oh and welcome to Pet Rooster club !!!! Sounds like you have a splash silkie roo !!