Breeders Tips and Links
Breeders Tips and Links
Studies / Science
Color Vision
there are sex-linked genes- chromosome named "Z".  Males carry two Z chromozomes
(ZZ), and females carry one (ZW).  Barring, Silver, and the Bantam gene are carried on Z.  
All males are ZZ and all females are ZW.  Since all offspring that inherit a "Z" from both
the female and the male will be male, only the male's chromosome will be in the female
offspring, since the female sent a "W" which does not carry the sex-linked gene.  
Therefore, the sex of the chick is determined by which chromosome the female donates
and the female offspring will always inherit the father's "Z" chromosome.  The male
offspring will all get a "Z" from both the male and the female.

Clear as mud ?

For example:  A Birchen male (carries 2 Silver alleles also written s+/*  --she has a Z
chromosome carrying a gold allele and a "W" chromosome without a color

OFFSPRING:  females will be 100% silver, males will be 100% mixed silver and gold.

** In the above cases, I would like to mention that we are not accounting for any of the
additional genes that make a Gold Birchen into a Black Copper (such as Mahogany,
etc.) which you would lose or greatly dilute when crossing.

Reference:  Sex linked genes  pdf

For more information on linkages :   Chicken genetics/linkages

Basic Mendelian genetics :

Eye facts/ Information :  Showbird

Five eye colors found in chickens:   pearl, red, brown, black and pink (albino).

Eye color is affected by age, genetics, diet and diseases.

Eye pigment is determined by three pigments:  Black from same melanin pigment that
makes feathers black, yellow from carrotenoid pigment xanthophylls, & red from
haemoglobin in blood’s red corpuscles. When there is no black or yellow, iris is bright
red from seeing blood vessels.

Condition known as “hen’s eye” is due to loss of iris pigment from laying eggs.This
helps explain why great laying hens seem washed out as laying progresses; color loss
in legs, combs, wattles, beak, eyes, skin, etc.

Be warned!!!
Selection for proper eye colorations should not be overlooked past simple compliance
to the poultry standards. Eye color is an indication of age (young chicks have what is
called “bull eyes,” dark eyes up until about 8 weeks of age), gender (adult males have
higher ratio of red corpuscles to white, so iris tends to be deeper red than
corresponding females), AND health. Marek’s (one form of this disease affecting eyes;
cloudy greyish, dilated, irregular pupil; distorted or blinded eye) and fowl paralysis are
sometimes accompanied by iris color degeneration. Cull from your breeding prospects
and do not breed from off coloured irises unless you are raising breeds that require
something like pearl colored eyes as listed in their SOP description.

When an eye turns to grey-green, it can be a sign of cancer (ocular lymphomatosis).
This kind of cancer produces a large number of fluid filled cells that by their presence,
obscure the sharp contrast of iris and pupil and/or pigment of the iris. This blocking of
seeing inside the eye may happen rapidly, slowly, in one or both eyes, and helps
explain why sometimes, one eye is affected, and not the other. Stress may incite the
condition to become more evident, simple stress from sexual maturity, moulting, laying,
etc. The eye color becomes exactly the same as seen in young chicks prior to maturing
into adult like pigmentation.

There is an old saying Dr. Carefoot quips in his book “Creative Poultry Breeding” about
breeding from older birds, “Never breed from pullets, themselves from pullets bred.” He
quotes this when talking about selecting birds to breed from (hens or at least pullets
that have survived the stresses of having gone broody or one moult cycle) and thereby
avoiding iris degeneration since it is associated with cancer and big liver diseases.
Trouble comes in the dark eyed breeds where lightening of the iris cannot be detected
so readily and thereby explains why in some inbred lines of Sebrights, large OEG and
Silkies, they have issues with Marek’s. Can’t cull against eye cancer by observing
changes in iris colourations in black eyes! VBG

Read more:
Here is a link to an interesting site with many articles on Chickens in general....including Flock
Management, Chicken Health, Incubation, Candling, etc.     
Scratch Cradle