What causes the feathers of my white Call ducks to turn yellow?

[c2231789]

My crested Call duck is currently kept indoors with limited exposure to sunlight. I've noticed that its feathers are starting to turn more yellow, unlike before when it was kept outdoors with some sunlight exposure. In our country, people commonly attribute this change to sunlight, suggesting that with sufficient sunlight, the feathers would remain white. However, I maintain some skepticism about this explanation.

I would like to inquire about the reasons behind this change.

 

[nuthatched]

Does she get access to water for bathing?
Why does she have limited access to sun?

 

[Fawkes]

I've seen it happen to free range white muscovies with access to a pond they swim in, so sunlight and lack of bathing can't be the only causes. Although, muscovies are known for not liking water as much as other ducks, but I'm pretty sure the aforementioned muscovies do regularly bathe.

 

[JacinLarkwell]

Does she get access to water for bathing?
Why does she have limited access to sun?

Sun can turn white feathers yellow supposedly

 

[c2231789]

Does she get access to water for bathing?
Why does she have limited access to sun?

I let him bath every day
I am keeping it indoors where sunlight doesn't come in.

 

[cheezenkwackers]

What does he eat? I am thinking that this is from excess carotene pigments. Corn, dark green vegetables, sweet potatoes etc. are high in these pigments. They are also what gives our birds the bright yellow-orange feet and bill and gives their egg yolks color. Years ago my Grandpa had cancer. He started drinking carrot juice several times a day because he heard it would help fight the cancer. His skin took on a yellow-orange tint from it. I suspect you are seeing something similar.
My brown duck’s feathers fade or bleach in sunlight. Maybe that is why people think sunlight makes white ducks more white, maybe it bleached them too.

 

[c2231789]

What does he eat? I am thinking that this is from excess carotene pigments. Corn, dark green vegetables, sweet potatoes etc. are high in these pigments. They are also what gives our birds the bright yellow-orange feet and bill and gives their egg yolks color. Years ago my Grandpa had cancer. He started drinking carrot juice several times a day because he heard it would help fight the cancer. His skin took on a yellow-orange tint from it. I suspect you are seeing something similar.
My brown duck’s feathers fade or bleach in sunlight. Maybe that is why people think sunlight makes white ducks more white, maybe it bleached them too.

Only commercial feed

 

[CoriM]

I have two white Duclairs who lead an identical life, one if buttery yellow since she molted a few months ago and the other is much whiter.