The gene for blue is a fantastic gene for many reasons. First it's an "in your face gene". You can tell if a chicken has it or not, just by looking at it. There is no need to do test matings to find out if it is present. This is the dominate blue , the one that effects black only, having little effect on red. One gene will change a black bird to blue where 2 genes will change black to a whitish bird with splashes of black/blue. It is best known as the "Andalusian Blue", not the dilute gene that is recessive, that changes both red and black. The dilute gene is best known for changing a Mille Fleur to the Porcelain color.
What other gene will give you 3 different possible colors, depending the number of genes for blue a bird has. If the gene isn't present in a chicken, then the chicken is black, mottled, mille fleur, or b b red, etc. If one gene is present, it will be blue, blue mottled, blue mille fleur, or blue red etc. If the bird gets 2 doses of the gene it is a splash, splash mottled, golden neck, or blue pyle etc. Another variety that depends on having 2 doses (having the gene twice) is red saddle, through it is seldom seen today.
Another nice thing about it is it is not sex-linked. As long as a parent has it then about 50% of the offspring should have it. A blue male will pass the trait on to both his sons and daughters. The same holds true for the female that has it. This is unlike the barred factor, where the male will pass the trait on to his sons and daughters. However the female will only pass the trait on to her sons.
There are several different matings that can be used for the blue gene. -1- Blue X Blue. This will give you 25% black (without the gene) 50% blue (with 1 gene) and 25% splash ( with 2 genes).- 2 - Black X Blue. This will give you 50% black and 50% blue. - 3 - Black X Splash. This will give you 100% blue.- 4 - Blue X Splash. This will give you 50% blue and 50% splash.
Many breeders don't like the Blue gene. In part because they don't understand it. Some want their breeding pens all one color. But then they will keep several different breeding pens with each pen being a different color (variety ).
Because of this, the 3 different color combinations can be maintained in one breeding pen. There is no need to keep each color separate. A blue male with 1 black hen and 1 splash hen will produce all 3 color variations, as will a blue male with a blue hen. What other gene allows for 3 different colors from one breeding pen.