Darkgreen opaline cock x Lightgreen hen

The facts

Sire: darkgreen opaline cock
Dame: lightgreen hen

Expected offspring

darkgreen cock/opaline
lightgreen cock/opaline
darkgreen opaline hen
lightgreen opaline hen

Observed result

violet cock
darkgreen opaline-cinnamon hen
lightgreen cock

Analysis

There is one big surprise: violet. Another new factor is cinnamon.

Violet

Violet is a strange colour. There are three ways to get a visual violet:

skyblue double factor violet
cobalt single factor violet
cobalt double factor violet

In a green series bird, a violet factor resembles a dark factor. This means the lightgreen hen can't carry the violet factor. So the visual violet chick can't be a double factor violet. This only leaves the cobalt single factor violet where both the darkfactor and the violet factor come from the cock. So the 'darkgreen' cock must actually be a darkgreen with a violet factor.

A visual violet also means a blue series bird. So both parents must be split blue

Sire: darkgreen violet opaline cock/blue
Dame: lightgreen hen/blue

Cinnamon

Since a opaline-cinnamon hen is born, a sex linked trait, the father must be split

Sire: darkgreen violet opaline cock/blue, cinnamon

Conclusion

Sire: darkgreen violet opaline cock/blue, cinnamon
Dame: lightgreen hen/blue

Expected offspring
The darkfactor and violet factor from the cock will result in offsping with both (25%), only darkfactor (25%), only violet factor (25%) and without both (25%).

25% of the offsping will be blue series:

green
green/blue (x2)
blue

_{(x2) means twice as probale as the other lines.}

Since for a visual violet you need a blue series bird with both the darkfactor and the violet factoer, the chances for a visual violet is 6.25% (= 25% x 25%)

The other factors (opaline and cinnamon):

cock/opaline
cock/opaline-cinnamon
opaline hen
opaline-cinnamon hen