Have you ever seen flamingos in the wild or in captivity
You will notice their beautiful pink feathers, but some seem more pink than others.
Not only do their colours range from very pink to a dull sort of pink but when a flamingo is born you see its original true colour
This being greyish (And Kind of weird looking)
So how do flamingos then turn pink at a later stage ?
Its all about what they eat
There is something called canthaxanthin which is a natural pink dye which is found in high doses in their food - brine shrimp and blue-green algae.
TL : DR version - Flamingos are actually born grey , they get their coloration from their diet of brine shrimp and blue-green algae and only turn pink later on.
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Source :
http://www.sciencefocus.com/qa/why-are-flamingos-pink
http://wonderopolis.org/wonder/pink-flamingos