It isn't a fantastic translation I found of a German information on Google but it could nevertheless be interesting for you:
Flamingos are among the most beautiful birds in the animal kingdom. They look like pink storks. Even her name sounds a bit like "Flame". But not all Flamingos are fiery red. There are also species that are rather light pink.
And some flamingos are even almost white, with some gray spots on the neck. These are the Flamingo children. If flamingos hatch from their egg, they still do not look like flamingos. Instead of pink feathers wearing a gray-white dress down. They are more like a small swan with long legs.
To turn red, they must only eat paint! Flamingos eat anything so in the water swims: mosquito larvae, algae, small crustaceans. In the algae and the crabs are called "carotenoids" in it, which are red dyes. The liver converts the Flamingos these dyes into tiny parts and these particles migrate into their feathers.
With the flamingos at the zoo, it is a bit tricky: It would be totally complicated, to get you the right algae places and enough small crabs to feed. But without the red color in the feed are flamingos white again! It used to be mixed therefore the flamingos in the zoo carrot juice in her dry food. Today is mixed directly into the red dyes.