Cuckoo-silverpartridge

Color and pattern male

Plumage: basicly similar to silver-partridge.

Neck: each hackle feather has a banded interruption, with the greyish-white bands merging into the greyish-black bands, the sharpness of the pattern and the intensity of the shaft-stripe are not high requirements, the shaft-stripe, if present, ends in a point near the tip.

Saddle: each hackle feather with a more or less distinct shaft-stripe pattern, also  banded interruption with a greyish-white color; absence of pattern is not considered a fault.

The barred pattern can be present in both purebred and impure males, which are allowed:

- Purebred male, the lighter bars are bright greyish-white and clearly wider than the dark-gray bars; the overall appearance is light in color.

- Impure male, the lighter bars are greyish-white and clearly narrower than the dark-grey bars; the overall appearance is similar to the color and pattern of the female.

Serious faults in males

- Purebred male: sickles and/or steering-feathers mostly white; completely off-color feathers; yellow or rusty-brown tint in the ornamental feathers.

- Impurebred male: white in the tail and/or wings; insufficient cuckoo-pattern in the wings, tail and breast; completely off-color feathers; yellow or rusty-brown tint in the ornamental feathers.

In addition: for both purebred and impure males excessive extra white pattern in the breast, resulting in an irregular cuckoo pattern. Insufficient cuckoo-pattern on wings and tail.

Faults 

The above serious faults occur to a lesser extent.

Color and pattern female

Plumage: basicly similar to silverpartridge.

Shoulders, wing-coverts, wing-bar, tail-coverts, saddle and back: alternating light grey, greyish-white clouded, with dark-grey peppering.

Breast: as evenly as possible light salmon-colored, transitioning to ash-silver at the thighs.

Down: greyish.

Serious faults

Red or rusty on the wings. Brown sheen on the back, saddle and wing-coverts. Yellow tint in the neck-hackle. Too coarse or clumped peppering. Absence of cuckoo-pattern on the wings and tail. Extensive cuckoo-pattern on the breast. Very light breast color. Extensive white in the pattern on the back, shoulders, wing- coverts, saddle and tail- coverts.

Faults 

The above serious faults occur to a lesser extent. Slight veining in the breast.

Genetic code: https://kippenjungle.nl/Overzicht.htm

Website with all available information regarding chicken genetics including the chicken color calculator.