The short answer for a Pekin duckling
A young Pekin duck is ready to leave its mother at about seven to eight weeks, when its feathering is complete and waterproof and it is feeding entirely for itself. Pekins grow faster than any other common duck breed, and the speed is deceptive: a duckling can look like a small adult at five weeks while its feathers are still letting water through to the skin. The mother, for her part, usually winds down her close attentions around five to six weeks, so the last part of the wait is about the duckling's plumage finishing, not about the bond breaking.
Growing at Pekin speed
A Pekin duckling's first weeks are a study in rapid construction. Hatched small enough to sit in a cupped hand, it multiplies its weight week after week on its way to being one of the heaviest domestic ducks, and its mother shepherds it through that growth by leading it to feed, water, and shelter rather than by feeding it herself. She keeps no timetable for any of it; she simply broods the ducklings less as they need it less, and by the time they are crowding her at the feeder as near-equals, her work is effectively done.
The swim test that decides readiness
Before a young Pekin is rehomed, give it the test that actually measures the thing that matters. Let the duckling swim in clean water for ten minutes or so, then lift it out and part the breast feathers: on a ready bird your fingers meet dry skin and the duck shakes, preens, and settles without a shiver. On an unready bird the feathers are sodden, the skin is wet and cool, and the duckling wants nothing but warmth — that bird needs another week or two of growing, regardless of how imposing it looks standing on the bank.
Moving a bird that has never been alone
Rehoming a young Pekin succeeds on company and continuity. Ducklings imprint on their group as much as on their mother, so send at least a pair, and preferably the group that has been swimming and sleeping together, because a single Pekin in a strange pen calls hoarsely for days and eats poorly. Send their current feed with them and tell the new keeper to change it gradually if at all, since a Pekin's growth depends on uninterrupted eating and a hunger strike costs condition fast.
Where Pekin timing goes wrong
Size is the great liar with this breed, and rehoming on looks at five or six weeks is the mistake behind most chilled, failing Pekin ducklings — the swim test exists precisely because eyes cannot judge waterproofing. A subtler error is holding the whole batch until the slowest duckling feathers out, leaving the finished birds crowded in fouled nursery bedding for a fortnight past their readiness; splitting the batch by readiness, keeping groups intact, serves both ends better. Sending ducklings to a home that expects them to live like chickens — no bathing water, perches, dry-litter-only housing — is a placement mistake that no timing can fix, and a brief, honest conversation before handover day prevents it.
What a fast-grown duckling's record should say
A young Pekin's new keeper should receive its hatch date, the feed it has been growing on, how its feathering progressed, and any individual notes — the duckling that was slow to waterproof, the one that had a wobbly day as a tiny and came right — because a bird that grows this fast generates real history in eight weeks. If a rehomed Pekin stops eating, withdraws from its companions, or develops laboured breathing, its new keeper should get it to a veterinarian quickly and be able to answer when it hatched and what it has been fed without phoning you from the waiting room. Passing those details over through KinsLe's Transferrable Profiles keeps a Pekin duckling's short but eventful early record attached to the bird itself, so the next keeper — and the next — starts from the facts.