The Roving Rototiller

Sunday, May 8, 2011

Valentine's chicks

After a long enough wait to make everyone a little nervous--twenty-four days!--Valentine finally has chicks.  I don't know what the delay was all about; normally you can expect a hatch at twenty-one days of incubation, especially under a hen, but for whatever reason Valentine's kids took their own sweet time getting here.  Fortunately for them, Mother Knew Best, and didn't let a piddling detail like a deadline get on her nerves.  And here is her reward:  four sturdy, fat little fuzzballs showing her their full appreciation on Mother's Day, as only little kids can:

Let's all sit on Mom!

These chicks are not from eggs that Valentine laid . . . not that she cares.  They are from our barred Rock hen Checkers, and the father is Jake, one of our blue Andalusians.  The color genetics are going to be interesting this time around, I can tell.  About the only thing that the two parents agree on is that blue modifies black. 

Blue, in chicken coloration, is actually more of a steely gray; it's blue in the way that a Russian Blue cat is blue, which is to say, not exactly what you would call blue.  But it's a very entertaining gene to work with.  Basically, blue is a gene that modifies black coloration, and it's a dominant gene, so it shows its effects even if there's only one copy of it.  If a chicken has no blue gene, then that lack is shown on a genetic diagram as bl+/bl+.  That little plus sign doesn't actually mean plus, in genetics.  Instead, it indicates consistency with wild type coloration.  Chickens that are colored like their ancestors, the junglefowl, have no blue gene at all.  Therefore, a bird lacking blue isn't just written as bl/bl, it's bl+/bl+, and a bird with one copy is Bl/bl+.  

In a Bl/bl+ chicken, every place on the body that was going to be black, is blue instead.  If, on the other hand, a chicken has two copies of the blue gene (Bl/Bl), then the result is a rather grubby white with random dark gray feathers mixed in.  This coloration is called splash; I think that's rather appropriate, because it makes the chicken look like it's been doused in dirty dishwater.

Jake, being a blue Andalusian, is Bl/bl+ and he is shades of blue all over.  Checkers, on the other hand, is a barred hen:  basically a black bird, with a barring gene that gives her the white stripes.  The barring gene is located on the Z chromosome, and because birds just have to be different, the female is the heterozygous gender (ZW) while the male is homozygous (ZZ).  (In mammals, the male is heterozygous (XY) and the female homozygous (XX)).  That means that Checkers only has one copy of the barring gene to donate, so each of these chicks has a 50% chance of having inherited the barring gene.  And at this point, there's no definite way to tell which ones, if any, did.  Barred Rock chicks are black with yellow tummies and a yellow splotch on the top of the head.  Three of these have the splotch, but we'll just have to wait and see if that corresponds to barring!  Even if it does, I anticipate "interference" from other genes from Jake's side of the family that would make the barring muddy, or alter how well it shows up on different parts of the body.  I don't know if there is any such thing as a blue-barred chicken!

The chick to the far left in the photo above is a blue, and the two in the background look like darker versions of blue.  The one in the foreground is black.  The paler down on their bellies is just baby clothes and will go away when they feather out.  It will be interesting to see what markings they all develop over the next few months!  (And of course, we're praying that most of them are hens.)

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