"Vent-sexing," the examination of a newly hatched chick's sex organ, should only be attempted by a trained specialist, as the process can cause permanent injury or death if handled incorrectly.
It is wise to keep more females than drakes, because the drakes can become sexually aggressive during the breeding season. If there are not enough females, the ones you do own may end up being injured by the drakes. A ratio of three females to one male is recommended.
The Indian Runner Duck is extremely distinctive. It runs instead of waddling; cannot fly; has a remarkable, upright posture; and it has a very long neck. In fact, their almost comical look meant that they were originally called "Penguin Ducks." The breed originated in Malaya and is thought to have been first brought to Great Britain in the early 19th century by a returning ship's captain. It's wise to know a little about Indian Runners if you're interested in keeping them, including how to differentiate between the sexes.
Once Runner Ducks are six to eight weeks old, it becomes possible to distinguish the males from the females by listening to their voices. Females are the only ones who can make the distinctive, loud "quacking" sound for which ducks are famous. The males, or "drakes," can only make a much quieter, whispering sound.
Indian Runner Ducks gain their adult feathers, or "plumage," by the time they reach the age of four to five months. A drake's plumage will always contain at least one notably curly feather at the end of the tail, while the females will have no such curly feathers.
The drake is also, on average, also slightly heavier than the female. A fully-grown male can weigh up to 2.3 kg, compared to the female, which generally weighs no more than 2.1 kg.
Adult female Indian Runners lay an average of 200 eggs per year. The males do not lay. The breed's egg laying can be a problem, as Indian Runners have a tendency to lay eggs wherever they happen to be and leave them on the ground.