Here is the breeding guide when breeding BLR or chickens with the Andalusian blue gene:
Blue X Blue = 50% Blue , 25% Black , 25% Splash
Blue X Splash = 50% Blue , 50% Splash
Blue X Black = 50% Blue, 50% Black
Splash X Black = 100% Blue
Black X Black = 100% Black
Splash X Splash = 100% Splash
These numbers are based on 100 chicks. Results will vary depending on number of chicks raised.