Yes, the white sports are the result of the recessive white gene that used the genetic symbol [c]. A white Legbar could also be created using the dominant white gene that has the genetic symbol , but that would require them being crossed with a white breed to introduce the dominant white gene.
When creating white varrieties they are often build starting with a blakc bird and adding, dominant white, recessive white, self blue, barring and other diluters so that there is no leakage of black color anywhere on the bird.
The Cream Legbar have White Leghorns in its creation and the North American lines possibly have White Leghorns out crosses in thier line too. Many of the White Leghorn lines are build with multiple dilutors. The dominate white from any such outcross or from the origins of the breed is easily breed out, but the recessive white can be passsed from generationt o generation with out ever showing up. If you assume that one in 10 Cream Legbars in the US have the recessive white gene is is easy to see how you would have a 90% chance of selecting a cockerel that doesn't have it. In so doing you may have 2-3 hens that have the gene and pass it to the next generation with out any offspring ever showing white. Eventually one of the offspring with the gene could be stelected as the breedin cockerel and if 1-2 hens in his flock also have the gene then you will start to see the white gene offspring to come out.
I have heard one person say that blue eggs seems to be linked with the white gene. I haven't seen anything to confrim that claim, but someone on this thread may have looking into that.
White the recessive white is not a leathal gene, I know that some people are haveing a hard time breeding the White Legbars in the US. Again I am sure that people who have worked on the white Legbars will be able to prive their insight.
