Growth in Dogs: Vet’s 2025 Guide to Puppy Development Stages & Milestones 🐾 

By Dr. Duncan Houston BVSc

Hello—I’m Dr Duncan Houston BVSc, veterinarian and Ask A Vet founder. Watching your puppy grow is a joy—but knowing what to expect at each stage helps ensure their health, training, and nutrition are on track. Here’s a vet‑approved growth guide that covers:

• Physical, behavioral & sociala milestones
• Nutrition & teething justifications
• Breed‑size differences in growth rates
• When to transition foods & vet visits
• How Ask A Vet supports healthy development

1. Neonatal Stage (0–2 Weeks)

• Puppies are born blind, deaf, and rely completely on mom for warmth and feeding; they sleep ~90% of the time.
• Most double their birth weight by day 10–14.
• Monitor weight daily or every other day to ensure proper growth.

2. Transitional Stage (2–4 Weeks)

• Eyes begin to open around day 10–12 and ears by day 14–16; by four weeks they begin to walk and bark.
• Puppies start nursing less and sample soft food by week 3–4.
• Self‑elimination begins rather than scratching the stimulus from mom.

3. Socialization Stage (4–12 Weeks)

• Puppies explore, play with littermates, and teethe; most baby teeth are present by 8 weeks.
• Critical fear period begins around 7–8 weeks—introduce age‑appropriate gentle social stimuli.
• Ideal window for early housetraining, basic commands, and positive exposure.

4. Juvenile/Adolescent Stage (3–6 Months)

• Puppies grow with rapid weight gain; by 4 months, they may weigh ~twice their adult weight mark.
• Teething continues; adult teeth erupt, and baby teeth may need extraction ~6 months.
• Training remains a focus as puppy confidence grows.

5. Teenage Stage (6–9 Months)

• Height and muscle maturity surge; adult coat replaces soft puppy coat.
• Adolescent behaviors like testing boundaries and destructive chewing may surface.
• Spaying/neutering is typically recommended during this phase.

6. Young Adult Stage (9–18 Months)

• Small/medium breeds generally reach full size by ~12 months; large breeds 14–18 months; giant breeds 18–24 months.
• Energy levels stabilize; adult food transition is appropriate—timing depends on size-breed demands.
• Bone and joint maturity solidifies—avoid excessive high-impact exercise.

Nutrition & Monitoring Throughout Growth

• Feeding puppy‑formulated diets until fully grown—twice calorie needs up to 40% of adult weight; taper down as growth slows.
• Monitor body condition and monthly weigh‑ins until 6 months, then every 2–3 months.
• Ensure balanced nutrients—protein, DHA, calcium‑phosphorus ratios—supporting bone, joint, neurological, and immune growth.

Ask A Vet Tracking & Alerts

• Growth milestone chart—capture height, weight, teething, behavior changes by week/month
• Feeding logs to align nutrition with growth spurts
• Alert triggers for retained baby teeth, slow/rapid growth deviations, or body-condition alerts
• Reminders for vaccinations, deworming, spay/neuter timing

📌 Final Thoughts from a Vet

Puppy growth is a complex, exciting process—from helpless neonate to confident adult. Monitoring physical, behavioral, and nutritional milestones by stage helps safeguard their health. Ask A Vet’s tools empower you to track progress, receive alerts, and ensure your dog thrives naturally and safely through every phase. 🐕❤️