In Brahma, Partridge colouring typically refers to the Gold partridge (black pencilling over a gold base) however we also have Blue Partridge and Splash Partridge too. 
The Blue Partridge differs as these birds carry one copy of the blue gene creating the steal blue/ grey colour over the gold instead of the black in the pencilling. 
Splash carries two copies of the blue genes when this occurs, the colours of the bird change completely and most of the pencilling is gone, instead you are left with a beautiful light coloured bird with orange patches and some dark tail feathers in the roosters.
Our partridge breeding pen only includes Gold birds and you will hatch only hatch Gold birds. . 
Partridge breeding ratios: 
Partridge x Partridge = 100% Partridge
Partridge x Blue Partridge = 50% Partridge and 50% Blue Partridge
Partridge x Splash Partridge = 100% Blue Partridge
Blue Partridge x Blue Partridge = 25% Partridge, 50% Blue Partridge and 25% Splash Partridge
Blue Partridge x Splash Partridge = 50% Blue Partidge and 50% Splash Partidge
Splash Partridge x Splash Partridge = 100% Splash Partridge