They are still hard to find but Th. Rutten and Son from Groesbeek still have a wealth of pure Janssen Gebroeders pigeons on their loft

Especially for Pigeon Bids, they bring 9 pure Janssen Gebroeders birds into auction. 

The well-known breeding lines of "Septemberman", "Princess", "Irna", "Adriaan",  etc....