The whole litter of Sandemann's rabbit and the silver male was black, and the original Havana mother had died when the offspring were ten weeks old.
In 1917, the DLP and in 1924 the Reichsverband Deutscher Kaninchenzüchter (Rich Association of German Rabbit Breeders) recognized the race under the name of Fee de Marburg and published the federal standard.
Van Piggelen, and the two friends therefore decided to raise and work with these unusual colored rabbits, and with the help of other breeders from the region of Gouda and Utrecht, they ended up creating the Gouwenaar breed.
By continuously working with these black rabbits, she later discovered the "blue bunny with a pink reflection" after generations of offspring, which she found very pleasing.
It was officially called 'Petit Gris' in French (Little Grey) and 'Rabbit Fairy' in the German text, with both containing a description of the inconsistent color that is used to describe the rabbit's fur.