Their beaks can be different colours, including greenish.
There is also a white feathered variety of the duck with an orange bill.
Laplaigne Ducks originated in the often-marshy fields bordering the Escaut (aka Scheldt) River in the area of Tournai, Belgium.
During the summer, they were let forage for themselves, particularly for worms. They were brought into enclosures in November for fattening for winter sale, and then sent to markets in Brussels and London.
The standards for the breed were roughly defined by breeding done starting in 1873 by a breeder in Ypres named Aimable Dervol.
There was intensive raising of these ducks in the area before World War One.