As far as I know there are no lethal alleles associated with the Andalusian Blue dilution factor. If you want more blues and splashes then you will want to breed accordingly. black X blue will yield about 75% blacks and 25%blues; blue x blue will yield about 25%black/50%blue and 25%splash; blue x splash will yield about 75%splash/25%blue and splash x splash will breed true 100% splash. These percentages are approximates, I have been breeding blues for 10 years and have over the years bred down to one blue hen which tells you that the percentages do not work out perfectly. Some birds are more prolific at passing the dilution factor to their offspring than others, when you find a bird that passes the blue dilution factor very well it is best to raise as many chicks from that bird as possible. The best color of blue comes from the black X blue cross but the other crosses will work for getting color but they will continue to dilute over the generations so black will need to be bred back into the line occasionally to keep the best color and lacing.
These percentages also came from the top of my head as I didn't do the calculations to ensure their accuracy but I believe they are right.
I have my last pair of blues mated together, knowing my luck all the chicks will be black
There has been some talk of large gold laced and silver laced and who has the best birds, I know there are several people from the east to the west coasts working on them but the base breeding stock out there is fairly small compared to the standard and the type is in need of work as well. I have see the rare picture of a nice fluffy female with good size but the lacing would be lacking and the color too light. I believe the silver laced could be improved by crossing with the silver laced wyandotte. There are very nicely laced strains of wyandottes out there to improve the cochin lacing and if you look there are strains that have more fluff and cushion than is prescribed in the standard for wyandottes. You will loose some of the feathering in the shanks and toes but this can be easily put back in a couple of generations and the combs will take a couple of generations as well. Back in the days when wyandottes were being made cochins contributed to their genetics and maybe it is time they give back to the cochin to help the gold and silver laced.
Blacks, Buffs, Blues and Whites currrently have the best type as in most instances the solid colored birds do. Partridge would be next with some pretty good birds on the east coast and in the upper mid-west. Reds are very rare with only a couple of breeders that I know of working on them. Brown Reds exist in very small numbers as well, while they are fairly common in bantams. Browns no longer exist that I am aware, however I am working to correct that. Mottleds are not yet recognized by the APA in large fowl but there are several of us working towards that end so maybe in a few years they will be.
In short the rarer varieties need more people working on them, it is not a matter of whether you can win a show with them, if you breed them to the standard and achieve that level of perfection and save the breed you have won and so has the breed/variety. Thanks for the nice birds Rudy, it was a pleasure meeting you at Shawnee.
Blessings to you all,