Lap-sized checks: under the tail first
Sexing a Nigerian Dwarf kid is the standard goat check done in miniature, and the tail tells the main story. Settle the kid in your lap — at this size that is the easiest position — lift the tail, and look at the skin directly beneath it. A doe kid shows two openings in a row: the anus under the tail and, just below, the vulva, a small slit with a tiny pointed tip. A buck kid shows the anus alone. Because everything on a Nigerian Dwarf kid is small, use bright light and take your time; the vulva on a days-old doe can look like little more than a crease until you know what you are looking for, and siblings checked one after another make the difference stand out.
The buck's belly button that is not a belly button
The backup check for a buck kid runs along the belly. Midway down his underside sits a small opening with a tiny tuft of hair, the exit of the sheath holding the penis — owners new to goats often mistake it for the navel, but the healing navel sits further forward and dries to a cord stump in the first days. Between a buck kid's back legs hangs his scrotum, and Nigerian Dwarf bucks are helpfully obvious here for their size: two small testicles in a distinct pouch, usually easy to feel with two fingers even in a young kid. If the tail says buck and the belly and pouch agree, you can be confident. If the pouch feels empty because the kid is cold or tense, warm him in your lap and feel again.
Why this breed's looks are a trap
Nigerian Dwarf kids defeat guesswork because the whole breed reads as dainty. Buck kids are not visibly coarser, doe kids are not visibly sweeter, blue eyes and fancy colours fall on either sex, and both arrive with horn buds or without depending on breeding, not sex. Behaviour in the pen — who mounts in play, who shoves at the teat — is kid behaviour, not evidence. Weight is no guide either in a breed where a thriving doe kid from a small litter easily outweighs a buck from quads. Even experienced keepers sex this breed by looking, not by impressions, and they look in good light with the kid still.
Getting it right matters sooner than you think
There is a practical urgency with Nigerian Dwarf kids: buck kids become capable of breeding surprisingly early for such a small animal, and an unnoticed buck left in with his sisters or his dam can produce pregnancies nobody planned. That is why the sex check belongs in the first days, not at weaning, and why a doubtful result deserves a second look within the week rather than a shrug. Mark the kids as you check them — a dab of animal marker or a note of which markings belong to which sex — because a pen of similar spotted kids scrambles anyone's memory by the next morning.
If you are still not sure
When the signs will not line up — a crease you cannot call, a pouch you cannot feel — wait a few days and repeat both checks on a warm, settled kid, and if it remains doubtful, have the vet or breeder confirm it at the first health visit rather than guessing on a sale or registration note. Kids are sold, reserved, and separated by sex in this breed from an early age, so a confident record is worth the small wait. Once settled, write the sex into the kid's record in KinsLe before the marker fades — months later, Pet Pass will still tell any buyer or vet which Nigerian Dwarf kid this is.