This is the time to introduce novel stimuli to the 
whelping box such as a plastic milk bottle, knotted 
towel, cardboard box, etc. This is also a time to 
introduce puppies to friendly cats. It is important to
continue picking up the pups daily, admire them, 
talk to them, and spend a few minutes with each 
one individually.

It is a time of very rapid sensory development. A stable 
environment is crucial. It is important not to overload them. 
Radical changes in the environment must be avoided, i.e. 
do not move the whelping box!
It is essential that the puppy remain with the litter and the mother.
Each day introduce a new surface such as concrete, linoleum,
wood, carpet, matting, etc. Taking them two at a time will make
it less stressful than  one at a time. Very mild auditory stimuli is 
introduced, such as a radio playing quietly.

Primary Socialization period - 3 to 5 weeks
Secondary Socialization period - 6 to 12 weeks

.

Puppy learns species specific behavior that makes him a dog 
(biting, chasing, barking, fighting and body posturing.

Learns to accept discipline from mother and to use 
submissive postures. Learns not to bite too hard.
Learns to relate to other litter mates and develops a
pack hierarchy through play.

Mother begins to wean puppies between 4-8 weeks,
but should be allowed as much time with the pups as she wants.
"This period is especially important for the development of a 
stable emotional 
 temperament and affective tone. Many social and emotional 
deficits observed in adult dogs are believed to result from 
removing puppies too early from the mother and littermates."

The 49th day. The brain waves of the puppy are
the same as a mature dog, but the puppy is a clean 
slate. Puppy should be completely weaned from mother. 
This is the age when most rapid learning occurs. 
Greatest impact on future social behavior will be 
made by any experience that happens at this point.

The window of opportunity is closing. Although 
puppies can continue to learn to be comfortable 
with new things, it is not as easy.

Best time to bring a puppy into its new home is around
week or 8. "The 49th day" is recommended by Guide 
Dog raisers and supported by studies.

Absolutely critical period in which puppy should be 
socialized - maximize this time! Enroll in a good puppy class!

Ideal time to capitalize on educating your puppy. 

Take into account puppy's physical 

Limitations and short attention span.

”From now to the 16th week of the puppy’s 
 Life, his basic character is set by what he is taught.
This will apply especially to his attitudes toward people
and toward his ability to serve them the very best he can."

Keep training fun. Use short sessions, and keep all training 
positive. Gentle guidance and management are essential. 
Set your puppy up to succeed. This kind of mindset will 
enable you to be successful, as you continue to socialize 
your puppy.

Puppies should not be shipped during this period, elective 
surgery should be put off until the 12th week, and necessary 
visits to the vet should be made fun.

So long as you provide structure, control and leadership, 
this transition should be relatively painless.

If these things have not been provided, all heck is about
to break loose!
Learning to compete 
 and cope.

 "Seems to forget everything previously 
learned."  Even if you have done your homework it 
does not mean your puppy won’t go through this - 
just be aware of it and ride it out. Just keep your pup
on a leash until this passes. This stage can last from a 
few days to several weeks and can occur anytime during 
this period. A puppy will test its wings. He may challenge
you in an attempt to resolve the question of leadership.
He may not come when called. He may not play fetch 
even though he once did. He will be uncomfortable 
because his adult teeth are growing in.

It is because of this stage that prevention over cure is advocated 
-- you must start socializing and training before now! When you
notice a change in your dog during this time, he is probably going 
through his "flight instinct" period. Like a teenager going through 
puberty, your puppy is changing physiologically. Your awareness 
of these changes in behavior will help get you through this 
commonly difficult period.
This is the time when obedience schools get most of their calls. 
Puppies that have not been socialized and worked with take a 
different path in life than pups that have.
Be prepared with appropriate chew bones (large enough so 
that the pup will not choke) to help with your pup's need to 
chew. Use a long line in the park if your pup is not coming when called.

May suddenly be apprehensive about new things 
or shy or timid of new people or situations. Most
of height growing is over, but pup will start to fill 
out over the coming year. Puppy begins to mature 
sexually: male begins to lift leg, and female has first 
heat period anywhere from 6-12 months. Puppy 
coat being replaced by adult coat, starting down the spine.

This is a fear of new situations and are handled with the 
utmost patience. The dog is encouraged to work it out on 
his own. If anything, it is better to ignore the whole situation 
than to reinforce the fear by praising the dog or petting him 
while he is afraid. When you "reassure" a dog with pets and 
"it's okay, fella", you are telling him it is okay to be frightened 
and you are creating a potential problem.

If your puppy appears apprehensive, avoid confrontation. 
Build confidence through training.
Avoid any potentially overwhelming circumstances you 
cannot personally oversee, such as shipping your pup in the 
cargo bay of an airplane.

 Are you done socializing? NO! Like your
training efforts, which continue on into 
adulthood and throughout your dog’s entire life, 
you are never done with socialization. He still needs 
to meet and greet people, go places with you, and 
continue to share your world and your experiences, 
if you want him to continue to be the happy, friendly 
dog he is today. Refers to sexual maturity as opposed
to being full-grown. Smaller dogs mature earlier, larger 
dogs later. If you were lax in your work earlier on, you
may now see the things you have missed: object guarding, 
unfavorable reactions towards unfamiliar people, animals,
or things that your dog missed during the socialization stage.

Until this period has been reached, it is
recommended that your pup remains crated or
the equivalent (structure) when you are not available 
to supervise his behavior.

You will know when your dog can be trusted by testing
him for short periods (10-15 minutes) while you leave the 
house. If your dog is damaging property while loose, he is not ready.