28/08/2025
CHICKEN COLOUR GENES ARE NOT MACHINES, they sometimes make little mistakes
Lavender is a true dilution (as ink in water) of both red and black (or blue, choc, dun etc) in the sense that less pigment enters the feather compared to when no lav is present.
Lavender is autosomal (the same in both s*xes) and recessive, one dose (lav/Lav+) does nothing. The gene 'lav' makes it almost impossible for pigment to move further from the pigment-producing cell to the keratin cell where the feather is formed.
Pigment: black and red gets stuck and only a few pigment granules manage to bypass the traffic jam in the pigment cell and still get through to the feather.
Unlike other 'dilutions', the colour of the pigment granules did not change. That means: red stays red, black stays black.
If a change from the virgin black or red was present, for example blue or choc or dun, or mahogany or cream for red pigment, the pigment granule changes colour (and shape too).
Here is another mechanism at work: the amount of pigment entering the feather is much less in a lavender. The pigments themselves, pheomelanine and eumelanine, did not change as in the dilutions and boosters.
Back to the photo, sometimes the pigmenttrafficjam dissolves and the normal amount of pigment can 'sort of' enter the keratin. That's why you see transverse stripes in the feathers of lavender chickens, suddenly some more pigment could enter the keratin. Why? Because that's how lavender's pigmenttrafficjamming works. You know chickenparts grow mostly at night... bones do...
In the photo of the shoulder of an isabel or lavender-coloured mille fleur'ish c**k, you can see that lavender was unable to trap red pigment.
I am sure there are more interactions between lavender and other genes that cause a slightly different phenotype than theoretically expected. An example might be lav and B (cuckoo), or lav and I (dominant white). With such combinations, you might see more pigment fuzziness compared to simple genes that don't affect pigment delivery from pigment cell to keratin in terms of timing or the shape of the pigment itself.
Simple explanations on how (colour) genes work: www.chickencolours.com - Genetics of chicken colours books available in several (not all) languages and a hardcover for the snobs.
