No, because Blue and Lavender are two different genes.shouldnt all of the ones from the barred hen be black since Blue comes from Lavender(recessive) and Black (dominant)?
The blue gene is an incomplete dominant: two copies of the gene gives splash (pale gray or white with bits of black), one copy of the gene gives blue, and no copies of the gene gives black. Blue is sometimes called "Andalusian Blue," because of the Blue Andalusian breed that is well known for having that color.
Lavender is a different gene (even though it is sometimes called "Self Blue".) Two copies of that gene gives lavender, one copy of the gene gives a black chicken that carries lavender without showing it, and no copies of the gene is just a black chicken.
The blue gene actually affects all black on the feathers of a chicken, so it turns a solid black chicken into a solid blue one, but it also turns a chicken with black lacing into a chicken with blue lacing, or a chicken with a black tail into a chicken with a blue tail, and so forth. It leaves the brown and red and gold shades alone. Lavender affects both black and red, so you can get some interesting pastel-looking color patterns (like Porcelain d'Uccles, which are basically Mille Fleurs with the lavender gene.)
If the rooster is blue, then he has one copy of the blue gene, and one copy of not-blue (=black.) So half of his chicks get the blue gene, and half get the not-blue gene (black). Because the mother is black with white barring, she must be pure for not-blue (black), which is what she passes on to all of the chicks.This would mean they inherit 2 copies of black.
(I keep calling the gene "not-blue" because there are quite a few genes where one version gives a different color, and the other gives black. So I tend to call them not-blue, or not-lavender, or not-chocolate, or not-Dominant-White, or whatever, to indicate which "black" I'm talking about. To have the chicken actually be black, it has all of those at once: not-blue with one pair of genes, not-lavender with another pair of genes, not-chocolate with yet another pair of genes, and so on.)
It's fun to have a bunch of colors like that!We had someone hatch out eggs from our Blue guy with eggs from 2 Barred, several red sexlinks and a new hampshire and got quite an unexpected mix of colors. I wish I could have been there to see which eggs they came out of.