Wow! interesting... so Brown is not a Buff Dundotte + DSV, it is a totally different mutation. (Here's what I meant with "creating"new color varieties with what I have).
Lavenders may or may not have a DSV, is there a way of proving that?
So there is no way that with this birds and its mutations that I have now that I may be able to hatch a buff/buff dundotte?
With what I have, can I select and eliminate DSV or it is linked to either Brown or Royal P mutations?
What is claimed is that Brown has the buff gene and the full dotting gene and a single DSV gene. The person that I know that has created browns did so by the mating of a Buff Dundotte with a Coral Blue. Her initial Browns had to have one buff gene, one blue gene, one full dotting gene and either one partial dotting or one no dotting gene. If a Brown does have a single DSV gene, it had to come from either the Buff Dundotte father or the Coral Blue mother.
If I was you, I would not worry about the DSV gene.
I believe that a standard Lavender has at least one DSV gene and possibly two and a Lite lavender does not have any DSV genes.
With your current group being:
Father: Royal purple (gray/blue, partial dotting/?, DSV/?)
Mothers (3): Brown (buff/blue, full dotting/partial dotting or no dotting, DSV/?)
The chicks are:
2 Pearl grey (gray/buff or blue, full dotting/partial dotting or no dotting, ?DSV),
2 Royal Purple (gray/buff or blue, partial dotting/partial dotting or no dotting, DSV/?),
1 Coral blue (blue/blue, partial dotting/partial dotting or no dotting, ?DSV) and
1 Lavender (blue/blue, full dotting/partial dotting or no dotting, DSV/?).
I do not believe that you can directly create a Buff Dundotte or a Buff from what you currently have. Depending on what your future hatches yield you might get a result that indicates that some of the offspring do have a buff gene. By selectively breeding them back to the Browns that you know have a buff gene, you will increase the odds of producing offspring that are homozygous for the buff gene. If you use the Lavender and the Coral Blue you will not produce offspring that are homozygous for the buff gene but if you breed the Lavender and Coral Blue together you will produce more Lavenders and Coral Blues that are homozygous for the color blue.