You do have a CCLB there, you won't be able to tell what sex until it gets some secondary sex characteristics as the white would hide the auto-sexing color distinction in the chicks, but as some of the previous posters noted, the color does occur. It is basically the same as the "isabella" or lavendar gene. Some natural or partridge patterend birds are heterozygous for this recessive gene, but as it is completely recessive, you don't see it (unlike the Black, blue, splash birds where the genes are co-dominant and heterozygous birds are blue). It is extremely rare in legbars as it will only occur if two heterozygous birds are mated and then in only about 25% of the offspring who inherit the gene from bot parent and are homozygous recessive. Because the resulting birds only carry this genotype, they will then breed true if bred to each other (like lavendar and isabella birds do). It is fairly well documented in Brown leghorns and partridge brahmas and crele orpingtons (very similar to what you would get in the legbar). See photos
