And they do have tougher shells that's why it takes the ducklings longer to hatch. please PM casportpony or Lacrystol both seasoned hatchers.
But hearing the badies means they have pipped internally so it's real important you keep humidity steady and not open the bator unless emergency...
Be sure to print out a sheet from the sticky's on caring for ducklings and give to each person who buys ducklings from you that way they know exactly how to care for them. especially this time of year.
and good luck selling them. Look forward to seeing them All. when they hatch...