Oropharma Yel-Lux is a natural yellow colorant based on luteine. This dietary supplement intensifies the yellow colour of the plumage and increases the resistance. When Yel-Lux is added to the food it is transported to the place where the feather is growing and it takes on the more intense yellow colour. The feather formed retains its colour until the formation of a new feather. Yel-Lux is not water-soluble and must therefore be mixed in the food.