My Cochin hen went broody in Jan sitting on 3 eggs and I brought her in tonight because the eggs were peeping well one is part way hatched I caught a glimpse when she scolded me for checking on her, lol. And to my surprise it was a blue silver colored chick with white feathers only saw the head and one wing so far. I'll get a better look when they are all hatched and dry. So whats up with that color my Cochin is white and I'm sure they are eggs laid by her, and daddy is a Cochin (partridge), or a blue copper maran. The Maran makes sense as far as the blue color I guess. But I was under the impression that blue was recessive and white was dominant so wouldn't the chick be white? Or am I wrong yet again.
Blue is incompletely dominant; white in cochins is usually recessive. However, dominance really has no bearing between these two as they are different genes, and dominance is related to alternative variations of the same gene.
The alleles for blue are blue (Bl) and not-blue (bl+). Blue is a diuter of black. If one blue gene and one not-blue gene is present, black pigment is diluted to blue; if two blue genes are present, black pigment is doubly diluted, to splash. If two not-blue genes are present, black pigment is not diluted. Whether or not white genes are present has no bearing.
There are a number of alleles for recessive white, but the only common ones are no-colour (c) and colour (C+). If there are two no-colour genes present, pigment is not created, therefore pigment cannot be diluted or enhanced because it isn't there. Kind of like trying to divide the number zero: you can't have parts of nothing .
Unless both copies of this gene are no-colour, creation of pigment is not affected.
Dominant white (I) works differently than recessive white. Pigment is created, but the mechanism by which it is transported to the feathers are faulty. Kind of like a whole group is trying to get across town and the bus that was scheduled to take them broke down. Some might manage to find their way anyways, but most will be no-shows at their scheduled destination. Dominant white works predominantly on black pigment, with minimal affect on red pigment. There are several dominant white alleles; I only mentioned I as that is what you are concerned about.
The base, or E-alleles present determine the primary distribution pattern of red and black pigment; however, other genes can modify this.
