There are two points in the life of any dog when the majority of personality traits of that animal will be shaped the most. The first comes during the time from birth to about eight weeks. It's common for people to ignore, over or under handle pups during this time and depend on mom for their physical and emotional development. Domesticated animals require more commitment then just constant petting, play or being picked up for the purposes of health examinations or treatments.
It depends on the breed and the individual, but most pups start to drift away from mom by four weeks of age. At that point the puppies should have access to an open area that includes mom, but doesn't severely restrict their movement. The pups should be able to wander freely for at least five feet from mom. This area should be inside a home or structure due to the danger of viral or bacteria infection and can be easily secured by a portable fence or gate.
Giving pups some exploration room also gives them a chance to gain confidence. With confidence comes the removal of excessive fear that every pup has as a natural protection against dangers earlier in life. Those without the ability to roam tend to retain that excessive fear resulting in a pup that is easily frightened and standoffish.
I recall many times in my childhood when a neighbor's dog would give birth. It was almost inevitable that the neighbors would find a cardboard box to place mom and her pups in. By the time the pups were five weeks old, mom had enough of her offspring and would leave the box for most of the time. The pups would climb out and get into all sorts of mischief. The result of trying to keep pups restricted to an area too small for them was not only frustrating for all involved, but caused the pups to be in the impossible position of fighting against their instinctive behavior.
Pups that are not given room to wander tend to grow into dogs that love to bolt. That's because they develop an instinctive fear of being trapped and will take every opportunity to get away when they can. Although dogs are domesticated pets, it's a mistake to believe that they are not largely driven by powerful instincts. These instincts can be manipulated for better or worse. Giving pups their space and allowing them to separate from mom is nature's plan and should be yours as well.
Proper socialization of pups should begin by the time they reach two weeks of age. If mom cooperates, you should begin to hold and pet each pup allowing a few minutes every day to let them know you are a friend. Soon the pups will look forward to these times and enjoy playing with you. Most puppies will not form lasting bonds with anyone until after they are sixteen to twenty four weeks of age, so there's no danger of having a pup get too attached to any one person. Unless you plan on naming or keeping the dog yourself, avoid using a regular term for an individual pup.
Sibling adjustment is an important part of personality development. This is the time during the first eight weeks of life when a puppy interacts with littermates. That interaction prepares the pup for life in the real doggy world and will determine how well a dog gets along with their fellow canines and other pets. If a pup is removed from its mom and littermates before seven or eight weeks, that dog is more likely to have problems adjusting to a new home. It will instinctively seek play time with littermates or mom (if it's a sole survivor) that are no longer around and this may bring on depression or even negative behavior patterns. Playing with people is not a good substitute for time with mom and littermates.
The next point of emotional and behavioral growth in a dog occurs when the puppy is transferred to a new owner or during the period of eight to twenty-four weeks of its life. During this time a puppy has to get used to a new environment, new odors and a different lifestyle. This may cause some stress and the symptoms that accompany it (throwing up, loose stool movements and a poor appetite) which may persist for up to a week.
Whether a pup remains with its Breeder or moves to a new environment, the period from eight to twenty-four weeks begins a new chapter in any pups life. During that time they will begin to establish themselves as self-sufficient individuals. Feeding and sleeping habits will be formed, territorial claims will be established and relationships with other animals formed. Positive reinforcement can be used during this period to let a pup know what is expected when it comes to compliance with acceptable behavior.
One of the biggest mistakes a new puppy owner will make is to confuse their animal. Most dogs are creatures of habit. They learn and thrive based on repetition. Constantly relocating food and water dishes, potty pans and sleeping areas will confuse an animal. Infrequent walks for those trying to train their dogs to go outside will cause your pet confusion. Dogs that cannot trust their owners to let them out or walk them will take care of business when and where they feel the urge.
Allow your pup time to itself. Dogs will often stare at members of their new family for what seems like an unusually long period of time. Most people assume this means that they want to be picked up or need something. What they are really doing is learning what you and other immediate family members look like. This, along with a powerful sense of smell, helps them understand which people are part of their family and which are strangers.
One of the first things a pup must learn is not to overreact to strangers. It may surprise you to learn that dogs which are allowed the most access to strangers are the ones most likely to bark at and possible attack them. That's because they do not understand that everyone who comes to your door or enters your yard is not an enemy. If you want you pup to get used to regular visitors who are not immediate family members, keep them away from the door while such people enter or exit the home. Allow them to smell and casually interact with regular visitors.
Dogs left out in a yard or in an area where they can view strangers when you are not present will bark in an attempt to warn off what they consider to be interlopers. Limiting their access to open areas while you're not home can help keep a dog's natural desire to protect their territory at bay. The two most important rules of dog ownership are to protect your dog against danger and to protect people against your dog.
Whether you are present or absent, you are responsible for your pet's well-being and behavior. Always be sure your pet has access to food, water and reasonable shelter. It's always wise to be sure your pup is in a locked area. This will make it harder for thieves to steal your animal and keep a reasonable separation between your pet and curious children. If your pet attacks someone whether it happens on your property or not, you will likely be held at least partially responsible. Keeping dogs on a short leash during walks is a common sense solution to most social interactions during walks. Keeping dogs kenneled during Vet visits or long car rides is also common sense solution to protect your animal and those who might try and interact with it.
The time to think about what a new puppy may need is before your purchase or adopt one. Depending on size, you'll need to be sure that your pup fits into it's new environment comfortably. Justifying a large dog in a small area by saying that you'll take the dog jogging with you is not responsible. There's always the possibility that an injury or change in lifestyle may eliminate that advantage and leave your dog high and dry.