In no particular order. Agreed, if a particular breed, or variety doesn't capture your full attention, move on. Life is too short to raise birds you are not enamored with. The 25% of the chicks that hatch black from a blue to blue breeding are still black, genetically the same as a chick from gold partridge parents.(With the possible exception that some old time breeders say a black chick out of a blue breeding seems to lack all the proper beetle green sheen that a black bird should have.) If you remove columbian from a single laced bird you get a double laced bird. If you add columbian to a pencilled (partridge) bird you get a columbian patterned bird. I have seen some folks describe a pencilled (partridge) patern feather as being double laced, which in fact is a completely different pattern.