I'm assuming you are brooding them together in the bathtub? They should be brooded separately but yes, when they live outside it will be much easier. The ducklings grow very rapidly and can trample over the chicks causing injury or death. If you feed your chicks medicated feed this can also harm the ducklings because they eat so much they can over medicate themselves.Right now mine are in the bathtub, not much room to seperate, so I'm hoping that makes a difference?