You are what you eat
They are considered the largest flamingo species. When it comes to flamingos, their food is responsible for the colour of their feathers. Crustaceans and algae contain the dye carotin. This is absorbed by eating and dyes the plumage a reddish colour.
When parents turn pale ...
Flamingos are social creatures and breed in colonies. Each pair builds a conical nest of mud. Their clutch is limited to a single egg. The parents feed their offspring with a predigested puree. This contains a lot of carotin which causes adult birds to fade while they are rearing their young.