Developmental stages of your Puppy 7-8 weeks Puppies require plenty of playtime with littermates, so they can socialize. Leaving the litter before 7 weeks can affect the puppy's ability to get along with other dogs later and they will likely have trouble learning to inhibit the force of their bite. The 49th day. The brain waves of the puppy are the same as a mature dog, but the puppy is a clean slate. Best time to bring a puppy into its new home is around week 7 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! Take into account puppy's physical limitations and short attention span. 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. 8 to 11 weeks This period falls within the human imprint period. Anything that frightens the puppy during this period will have a more lasting effect than if it occurred at any other time. 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. Experiences a puppy perceives as traumatic during this time are generalized and may affect him all his life. It is a fact that a dog is most likely to develop an avoidance response if subjected to physical or psychological trauma during these four weeks. 10 to 16 weeks Social dominance - 10 to 16 weeks 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!This period falls within the human imprint period. Anything that frightens the puppy during this period will have a more lasting effect than if it occurred at any other time. 4 to 8 months 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. 6 to 14 months Many dogs will show a rise in their level of aggression (reactivity) during this time. They may become protective and territorial, and may make a new attempt to dominate owners. Incidents of teenage flakiness may recur.In large breeds this period could extend longer since it is tied to sexual maturity. Incidents may occur more than once. Corresponds with growth spurts. Therefore it may happen more than once as the puppy matures. 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", 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. "The Handbook of Applied Dog Behavior and Training", Steven R. Lindsay. Instructor Training Course - Dr. Ian Dunbar, PhD. "How to Raise a Puppy You Can Live With." Clarice Rutherford & David H. Neil. "The Urban Puppy Toolkit". ( This list compiled by Accredited Training Instructor Drgnrdr with credit given).