i found this info on the internet...
"The ducklings should upon hatching be covered in yellow down with either a pink or orange bill. those that hatch with a orange bill may well loose the orange at a few weeks old. They will after about 5 weeks return to a bright orange, ducklings that have hatched with a pink bill will also change in bill colour after a few weeks to orange. The orange colour comes from lutine which is found in most leave greens.Grass being on of the best. It is therefore important that this is feed. "
"The ducklings should upon hatching be covered in yellow down with either a pink or orange bill. those that hatch with a orange bill may well loose the orange at a few weeks old. They will after about 5 weeks return to a bright orange, ducklings that have hatched with a pink bill will also change in bill colour after a few weeks to orange. The orange colour comes from lutine which is found in most leave greens.Grass being on of the best. It is therefore important that this is feed. "