Can I use another colour of brahma roo to cross with a gold partridge that I could breed and sell?

[NatJ]

For example with ausralorps you could cross and blue and a black and get a splash!

You got a few words in the wrong order here. The correct form would be to cross splash and black to get blue. A breeding of blue and black will give some blue chicks and some black chicks but no splash chicks.