Hold the duckling on its back with its head pointing down your wrist in your right hand and its legs up in the air pointing away from you.
Expose the vent by holding the tail up with your left hand, and pressing in and up between the duck's legs with the thumb and forefinger of your right hand. With very slow, gentle pressure, open the vent.
Observe the genitalia through the opening. Female ducklings have a cone-shaped organ that is more easily observable. Males have a smaller, longer, pointed organ inside a larger cloaca. The male's organ may not even appear for several seconds after the vent is opened.Do not attempt to put your fingers into the vent opening; this can cause serious injury to the duckling. Use only gentle pressure applied to the edge of the opening......Ree