Yes — keep one from the first weeks, because no common duck changes as quickly as a Pekin, and unaided memory simply cannot track a bird who seems to be a different size every time you cross the yard. Bred as a fast-growing meat duck and kept widely as a pet, the Pekin packs on weight early, and the log's job changes as the bird does: first it is a growth chart, and later it becomes a mobility and condition record for a heavy adult whose legs carry a lot of duck.
Logging the growth phase honestly
Weigh young Pekins on a low platform or in a held container on a scale, always the same way, and write the result beside age in weeks and what the birds are eating. You are looking for a steady upward line shared roughly by the group, with individuals flagged when they peel away from it. A duckling who plateaus while siblings surge may be getting pushed from the feeder, struggling with a leg problem, or falling ill — the log cannot say which, but it tells you exactly which bird to watch, separate, and feed where you can see the intake.
Note leg development in the same entry: splayed posture, reluctance to stand, or a young bird resting on its hocks while others move to water. Rapid growth and leg strain travel together in this breed, so gait notes beside weights give a veterinarian far more than either would alone.
The adult record: condition and movement
Once growth levels off, weigh less often and judge condition by breast feel and, above all, by movement. An adult Pekin should walk willingly to feed and water, get in and out of a shallow pool without drama, and spend part of the day actively foraging. Log an adult who increasingly sits while the flock moves, pants after short efforts, or develops sores from resting pressure on the breast or feet — those entries, dated by sequence in the notebook, show whether extra condition is starting to cost the bird comfort.
Keep feed changes in the record too. Pekins are enthusiastic eaters, and a generous hand with treats across several family members can push an adult past comfortable weight quietly; the log makes the household's combined kindness visible.
When entries should trigger action
A young bird off the growth line for successive checks, any Pekin whose walking deteriorates, an adult losing weight and appetite together, or a bird with discharge around the eyes or bill or labored breathing deserves prompt veterinary advice, with the log in hand. Separation for observed feeding is a sensible first step while you seek that advice, because it converts a suspicion about intake into a fact within a day.
For pet Pekins kept for years, the adult log also guards the opposite drift — slow, comfortable overfeeding — by keeping an honest number between you and the treat jar.
Storing a Pekin's growth curve, gait notes, and adult condition checks in KinsLe as a Pet Passport keeps the whole fast-moving story together for vet visits and anyone sharing duck care.