Sexing in rabbits rearing is the practice of determining whether a rabbit is a male [buck] or a female and is best done at 6-8 weeks from birth. How I do it or rather how is done: Allow the young rabbit to lie on its back either on a flat surface or along the knee. Then using thumb, press between the hind legs.
The appearance of a protrusion [the penis] from a small hole indicates a male rabbit. A female rabbit is shown by the appearance of a 0.5 cm long slit [the vagina]. Why do it ? Mating younger animals results in the producing of weak small ones hence sexing prevents mating and, in that matter inbreeding of young brothers and sisters within a litter. For they are segregated after identification through sexing.