Duck Genetic Question - What is going on with this duck??

[Jelibaen]

Hi everyone!

I have this duck that I am in love with, and have no idea what is going on with her coloring!

This is her tonight. She is a lighter tan, not really a buff, more of a dusty brown, but her feathers are turning white. It started as a few on her back, and now she is more than half white.

For context, this is her beside her hatch mate. They were both the same color in their first year.

I believe they have the same father (Could be a Swedish, could be a Khaki) but different mothers. The one with the white I'm starting to think could be a Cayuga mix, but her feathers are turning white way faster than any of my other Cayugas.

Is the colour changing to white thing strictly a Cayuga gene? Is there a different duck version of vitiligo?

If it helps, my flock had Cayugas, Swedish, Buff, Rouen and Khakis when she was hatched.
Thanks in advance!

 

[KathiQuacks]

Do you have photos of them in their first year?
Did the color change happen slowly over many months, or quickly, like during a molt?

The genetic white color change happens in all black-base ducks. This includes Cayugas, but also all Swedish ducks & certain Runner ducks.
Feathers can also lighten in the sun over time, getting replaced with darker feathers after a molt.

Just based on her current appearance & possible parents, I would guess she’s Khaki x Cayuga.

 

[Jelibaen]

Do you have photos of them in their first year?
Did the color change happen slowly over many months, or quickly, like during a molt?

The genetic white color change happens in all black-base ducks. This includes Cayugas, but also all Swedish ducks & certain Runner ducks.
Feathers can also lighten in the sun over time, getting replaced with darker feathers after a molt.

Just based on her current appearance & possible parents, I would guess she’s Khaki x Cayuga.

Her first year she was indentical to the other duck! This started as a few white feathers after her first molt, but has increased with every molt since.
She's turning white faster than any other duck, but still seems to be perfectly healthy.