Puppy Development From 8 to 12 Weeks

Puppy Development From 8 to 12 Weeks

The Spruce / Hilary Allison

During 8-12 weeks of age, many puppies join their new homes leaving their mothers, littermates, and infancy behind. During this developmental period, called the imprinting stage, the brain is rapidly developing, and the dog is impressionable and ideal for training. Many veterinarians recommend waiting until a puppy is at least 12 weeks old before having them leave their littermates.

The puppy is picking up its good and bad behavior tendencies from their experiences and environment during this critical learning period. It's important to take a look at a pup's physical and behavioral milestones, as well as its health and nutrition needs during this vital puppy stage.

Physical Development

An 8- to 12-week-old puppy will still be quite small, even if the puppy is a large dog breed. Puppies are physically vulnerable and a bit clumsy. They need plenty of supervision and crating when alone.


Expect your puppy to sleep up to 18 to 20 hours a day to support their fast-growing brains and bodies. Puppies at this age may seem to go from zero to 60 out of nowhere, then suddenly fall asleep within minutes of being in overdrive.

House Training

Before 12 weeks of age, most puppies will have trouble controlling their urination and defecation. They are prone to frequent accidents and cannot usually make it through the night without urinating. House training should begin as soon as you bring your new puppy home, but be prepared for the first few weeks to go slowly. Stick to a regular schedule, taking your puppy outside every time it eats, drinks, or wakes up from a nap. Take your puppy to a designated "potty spot." Reward them when they go in the right spot. After a few weeks, it will learn to have better control over its bodily functions.


Your puppy won't begin to get adult teeth until about 16 weeks of age, depending on the breed. Some of its baby teeth or "milk teeth" may start falling out between 8 to 12 weeks of age. Signs of teething typically won't start until 12 weeks old. You know your dog is teething when you begin to notice excessive drooling, excessive chewing, pawing at the mouth, and bloody residue left behind on chewed items.

Behavioral Changes

The time from 3 weeks to 12 weeks is a critical socialization period. This time is often called a "fear stage" as puppies may seem to be afraid of everything. Practice handling your puppy so it can get used to being held and touched in unfamiliar ways.

Expect your young puppy to react with fear in some situations, but avoid coddling or comforting a timid pup. Find ways to introduce new sights, sounds, and environments like vet visits, nail trims, and baths and keep everything positive.

Reward your puppy for relaxing in new situations and exploring new things. However, don't push your puppy to accept a situation that scares it. It will eventually learn that there is nothing to worry about if you remain calm and upbeat. Act as if the situation is regular and routine.

Health and Care

Between 6 and 8 weeks of age, your puppy will need to visit the veterinarian for its first puppy vaccines, deworming, and an examination. The breeder or adoption group might have administered its first vaccines and deworming and taken the puppy to the vet. Regardless, you should take your new puppy to your veterinarian within a few days of getting it to make sure it is in good health. Bring any records provided by the breeder or adoption group so your vet can adjust or prescribe a vaccination schedule.

Disease Prevention

By 18 weeks of age, the puppy should have all its vaccinations. But until then, you need to prevent exposure to diseases. Do not allow your puppy to walk in highly populated dog areas or interact with unfamiliar animals. Your puppy can play with healthy puppies and adult dogs that have been vaccinated and dewormed. Make sure you know the owner of the other dog and can trust that the dog is healthy.

Food and Nutrition

Puppies begin weaning off their mother's milk around 3 to 6 weeks of age and are typically fully weaned between 6 to 8 weeks. By the time you get your new puppy, it should already be eating puppy food for at least a few weeks. The breeder or adopter should provide you with information about the type of food it is eating.

Puppy Food

Start with the same diet, if possible. Allow your new puppy to adjust to its environment for a few days or weeks before you choose a new food. If you decide to change the food, be sure to transition to the new food gradually to avoid gastrointestinal upset.

Your puppy needs proper nutrition to grow and thrive. Provide a high-quality puppy food labeled for growth. Most puppies between 8 to 12 weeks of age should eat three times a day, spaced out somewhat evenly. This regularity in mealtime helps prevent blood sugar drops, especially in very small breeds.

How Much Should You Feed a Puppy?

Start by feeding the amount recommended on the packaging for your dog's weight. Check your dog's weight every few days to see if the feeding amount needs to be adjusted. If your puppy seems voracious and does not seem to be gaining weight, adjust by adding more food. Reduce the offering if it leaves a lot behind. At your veterinarian visits, discuss the type of food you are feeding, the frequency of feeding, and the amount you feed per day vs. the amount consumed. Ask your veterinarian if you need to make any dietary adjustments.

Homemade Dog Food

If you wish to feed homemade puppy food, you can, but you will need to do so very cautiously, as a poorly-constructed diet can be dangerous at this time which is why it is often not recommended. Consult with your veterinarian about the recipe you plan to use. Never assume a homemade diet you find online is properly balanced as most are not. You will need to make sure it is a balanced, nutritious recipe, using the right ingredients, and an adequate number of calories.


Your puppy can have a variety of treats as long as they are safe, non-toxic, healthy, and make up no more than about 10 percent of your puppy's daily caloric intake.


Even though your puppy is still a baby, it's essential to start training as soon as it comes home with you. Start simple. Teach your puppy its name. You should give the dog a couple of days to get used to the house rules, such as where it is allowed to go and where the forbidden zones are in the house.

Let it get used to the feeling of a collar before adding a leash. Then, you can start letting the dog drag the leash around, so it understands the feel of it. As soon as the dog seems comfortable with it, you can start training it to walk on the leash.

Although this is a rapid learning period, your puppy may not be the fastest learner at first since there are many "firsts," new scents, places, and people all starting to come into focus. You can even begin to introduce some basic commands like sit, stay, and down. Go slow, be patient, keep it positive, and have fun.

  • How long can a 12 week old puppy sleep at night?

    Many puppies won't sleep through the night until they're about four months old, so you will need to take it out once or twice until then.

  • How far can a 12 week old puppy walk?

    Puppies this age can walk for about 15 minutes. A good way to figure out how far your puppy can walk is five minutes per month of age. Therefore, three months equals 15 minutes. Make sure not to walk in the middle of a hot day or on pavement and pay attention to the weather just like you would with an adult dog.

  • How long can a 12 week old puppy hold their bladder?

    A 12-week-old pup can hold its bladder about four to six hours, so you will need to be walking it at least four times per day.

Watch Now: All You Need to Know about Puppies

Article Sources
The Spruce Pets uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Behavior Guide for Your New Puppy. Ohio State University Veterinary Medical Center.

  2. 2017 AAHA Canine Vaccination Guidelines. American Animal Hospital Association.