To Clodiloa (and others of course):
these male birds can have different alleles on the sex-linked gene lokated on the "S-locus".
They are most possible S/s+ for the cocks (but can also be S/S);
They are S/- for the hens, that is sure.
As Tunde said there can be also other genes involved when you can see "red" on Silver birds.
-First there is the autosomale red (Ar+) This is the red (salmon) you can see on e+ hens breasts and on eWh hens compleet body, also on the wings and shoulders of cocks with these basic colours you can see this kind of red (autosomale = on both sexes).
-Second there is the Mahagony red (Mh) This is a red reinforcer {(as well of the gold (s+) as of the autosomale red (Ar+)} This results in a darker version of the respective two reds.
It is not always so easy to indicate if it concerns gold (s+) our autosomale red (Ar+) we see on our birds.
About the Ar+ and the Mh we still not agree completely on the determination (because we read different books and studies) but it is a fact we both agree on the existance of it.
[Modificato da Danny_57 22/12/2008 10:41]