Please keep in mind that these phases of your puppies growth are very basic generalizations, different dog breeds will progress at their own natural pace.
Please do not assume that any instructional article or book contains the exact time frames and milestones of your pets development. Like you, like people, your dog is also unique.
The Afterbirth Phase: 0 - 4 Weeks Old
Oh, its so exciting, you have a new puppy. Your puppies eyes will start to open, and you will watch them begin to respond to sounds, light and movement within their new environment. They begin trying to 'learn their legs', how to move around. They start bonding with their mother and other puppymates, while becoming accustomed to their litter box. As much as you want to pick them up, cuddle them and take them around the house with you, its pretty important for the first month plus, to leave with them with their mother. You will have years and years to spend with them. This is a good time to start learning patience with your new doggie, your going to need it. puppy doggies
Around the third to fourth week you will really begin to notice your puppies senses will start to go beyond their litter box and become more alert to a wider environment. They really begin to recognize things and faces, especially yours, as well as other family members. They are starting to learn and develop their own dog sense during this time.
It is important to not have any unusually loud noises, unnecessary excitements, such as arguments, or any very rapid changes around your puppy. Your puppies development is very sensitive at this time. While you should not walk around on your tiptoes, talk in a whisper or avoid playing music or TV, as they need to become accustomed to the regular sounds of your household, you should be aware that their development and doggie personality can be negatively impacted if placed under undo stress.
The Doggie Socialization Phase: 4 to 8 Weeks
Around this time frame the mother will begin weaning her puppies and teaching them dog pack discipline. They will start learning the fundamentals of doggie pack socialization. They begin to understand that mom is not just there to take care of their hunger, but that she is the leader of the pack.
As Mom weans them you can gradually begin to start gradually feeding them. Ease them in to puppy dog food slowly, their systems need time to adjust.
During this period you can begin to handle your puppy daily, but even though you are still excited at this time, and want to cuddle them, they should not be separated more than 15 minutes daily from the litter. They are still learning doggie socialization, how to play with their mates, how to bite in a playful way and general puppy mannerisms.
If you want your puppy to grow up into a well adjusted dog, and who doesn't, it is very important to leave your puppy with its mom and litter mates for at least two months and if possible, a bit longer. There have been studies showing that puppies which have been removed from the litter prematurely tend to be more nervous, have a tendency to bite and bark more frequently, as well as having a little more difficult time being trained, compared to puppies that were able to mature properly within the litter.
Fear not, Little Doggie Phase Weeks 9 -12
Your may have to re-experience many things you thought you and your puppy has, been there - done that, lets move on to the next phase. And its up to you to re-adjust. While your dog is quite capable of learning very quickly, many dogs become very afraid of the very things that just seemed normal not so long ago. It seems like your taking a step backwards, so it is important that you take this in stride and make sure not to over-discipline your doggie.
There will be housebreaking boo-boos and play fighting that can get taken too far. But on the other side, your housebreaking training will become easier as your puppy is learning to control their bowel and bladder movements as well feeling more relaxed and being able to sleep through the night.
This is also a good time to begin leash training and the teaching of basic commands, sit, stay, down,come, etc., which will become reinforced behaviors through your positive responses. How you teach and respond to your puppy will influence their behavior in the years to come.
The Terrible Twos Phase 3 - 6 Months Old
Just as human babies, toddlers, are often renowned for going through what is called the 'terrible twos, your puppy will also begin to assert their independence. By now you have just spent quite a bit of time on their training, dedicated hours towards bonding and now, again, you will have to readjust.
Depending on their nature, your puppy will test the limits and try to assert their dominance over your commands and authority. It may appear that their natural urge to please you has all but disappeared. Just like that, you are ignored. Now is the time for a patient, yet firm hand. Let them know you are the leader of the pack and continue with a stronger reinforcement of training and commands. Another technique is to play hard to get, ignore them for a few minutes, if they do not expand to your instructions.
It is not only their mental dominance trait that is occurring, for bigger dogs they start to feel their own strength and will want to challenge you. While you might be playing at wrestling or tug of war, they may be actually testing too see who is stronger. Even if you 'win' the contest, they may perceive that its permitted to 'fight' challenge you. Watch for this type of challenge carefully, and if you feel like this can become a serious situation, for the time being, stop these kinds of activities. Remember though, each dog is individual and testing their boundaries is natural, so often times these kinds of activities are them just being playful.
Unless your doggie is in a confined area, now is not the time to let them off the leash. Too many horror stories of young dogs just taking off have unfortunately lead to their own injuries and even death.