How to Feed My Pet

What's normal week by week, birth to 16 weeks

Dogs & catsBirth – 16 weeks·Sources checked September 13, 2026
This is general information, not veterinary advice, and it cannot diagnose your animal. Very young puppies and kittens deteriorate quickly — when something looks wrong, contact a veterinarian rather than waiting to see if it resolves. Medical disclaimer

Everything below is a reference window, not a deadline. A puppy whose eyes open on day 16 rather than day 13 is not behind schedule. What matters far more than hitting a milestone on time is the direction of travel: steady weight gain, active feeding, and responsiveness.

How we label our evidence

  • Source-supportedStated directly in the cited institutional publication.
  • Our editorial guidanceA conservative reading of the evidence applied to a caregiver decision. Not a validated clinical protocol.
  • Evidence gapWe could not verify this in our approved sources, so we have not invented a number.

Puppies

Canine development reference windows (Merck, Cornell Riney)
AgeWhat to expect
Birth – 6 daysEyes and ears closed, movement limited, fully dependent on maternal care
13 – 19 daysEyes and ears open; motor control improves
3 – 4 weeksFirst deciduous canines and some incisors; may start exploring solid food
4 – 6 weeksRemaining deciduous incisors, then premolars, erupt
7 – 10 weeksCornell's usual window for weaning to be complete
~12 weeksJuvenile developmental period begins
~4 monthsSome permanent teeth begin erupting — not tied exactly to week 16

Puppies

Growth references. For the neonatal period — the first 21 days — Merck gives 1–3 g/day per kg of anticipated adult weight, alongside a shared neonatal figure of 5–10% of body weight per day. Across the broader first five months, a separate Merck chapter gives 2–4 g/day per kg of anticipated adult weight.

Those two figures describe different age ranges. Neither is a fixed allowance that applies to every breed, and a 3 kg-adult breed and a 40 kg-adult breed are not comparable on a raw grams-per-day basis.

Watch for: weight loss or stalled gain, difficulty suckling, persistent eye or nose discharge, markedly asymmetric movement, or the loss of an ability the puppy already had.

Kittens

Feline development reference windows (Merck, AAHA)
AgeWhat to expect
Birth – 6 daysEyes closed; needs maternal care and help to eliminate
~1 – 2 weeksEyes open. Merck says 7–10 days, AAHA says 10–14 — see the note below
2 – 3 weeksFirst deciduous incisors; motor ability improving
~3 weeksRemaining deciduous incisors and canines; voluntary elimination starts
5 – 6 weeksDeciduous premolars; litter-tray use becomes more independent
5 – 8 weeksMerck's weaning window
4 – 7 monthsPermanent teeth generally erupt — well past week 16
Source-supported
Merck and AAHA disagree on kitten eye opening — 7–10 days versus 10–14 days. We have not picked a winner. For practical purposes, roughly 1–2 weeks, with variation covers both, and the disagreement itself is a useful reminder that eye opening cannot be used to pin down an unknown birthday.

Kittens

Growth references. Merck gives a typical birth weight of 90–100 g and 50–100 g per week during early rapid growth — very roughly 7–14 g/day if you convert it, though it was not published as a daily pass/fail range.

Birth weight varies, and a weekly average can hide a recent decline. If you are weighing daily, look at the trend across several days rather than any single reading.

Watch for: reduced intake, stalled growth, weakness, marked tremor or incoordination, swollen eyes or discharge. Some congenital neurological problems only become apparent once a kitten starts walking.

When a milestone slips

What the action labels mean

Emergency now —
contact an emergency veterinary service and arrange immediate assessment. Do not wait for the next scheduled feed or weigh-in.
Call now for triage —
telephone the veterinary service when you notice the sign. The veterinarian decides how quickly the animal needs to be seen.
Contact today —
get in touch when you notice the issue to agree on a time. This does not mean waiting until evening.

Call now for triage

Weight loss at any age. Merck recommends weighing puppies twice daily in the first week and investigating weight loss promptly after the first 24 hours. Also call if the animal cannot feed, is unusually weak, or has lost an ability it previously had.

Contact today

Stalled gain in an animal that is otherwise feeding and responding normally. Re-check the scale and your weighing routine while you arrange advice.

Common misconceptions

  • "All puppies should gain 10 g a day." Expected gain scales with anticipated adult size. A toy-breed puppy and a giant-breed puppy are not on the same curve.
  • "Outside the window means something is wrong." These are typical ranges across many animals, not individual pass marks.
  • "The puppy timeline works for kittens too." It does not — kittens open their eyes earlier and wean earlier.
Evidence gap
We could not verify an exact first-walking date, a kitten ear-canal opening date, or a birth-weight-doubling deadline for either species in our approved sources. You will find confident numbers for all three elsewhere online; we have not repeated them, and we would not convert a percentage growth figure into a doubling deadline.

Sources