What should the first color variety should I introduce into my first round of Giant Silkies?
Maybe something solid-colored, because patterns don't show up well on silkie feathers.
I'd probably go with black or white for starters.
Recessive white might be easiest, if you just want to get it breeding true without spending much effort selecting for the best-colored ones.
But if you start with black, you can branch out into barred, and also blue/splash, and potentially also lavender, chocolate, & mauve.
Or you could go with Columbian because you're working with Brahmas anyway, so the color genes would not require any extra outcrosses.