When I started building my team, I learned that the pack instinct is an innate characteristic of the Inuit Sled Dog. The pack has a hierarchical organization which is developed over a period of time through a process of socialization. 

A pack containing several generations is ideal. A musher will start with an unrelated pair of adults and breed them. Parents and a selection of offspring - as few breeders keep the whole litter - will constitute the base of the pack. When I started my pack I chose a mature bitch and a mature male from different packs. I chose submissive dogs, not dominant ones. I kept three pups: a female and two males. This family has the run of a pen approximately fifty meters by thirty.

But for the first four weeks after she delivered, the bitch was alone in a pen with her pups. Then I let the male in. He was interested in the pups and was good to them. All the same, the bitch was very protective, keeping him away. 

By four months, the individual characters of the young dogs begin to show. Even earlier than that, it is possible to determine whether a dog will be submissive or dominant. From the moment they can stand, the pups play. These tussles mimic fighting. When they mature sexually, after six months, the play fighting continues but occasionally a fight for dominance occurs. If there are two or three young dogs in the pack, they will fight seriously for a few months until they have determined their hierarchy. The adult male is the boss and will usually intervene and break up the fight. At feeding time, I picket the adults. When they have finished, I let all the dogs socialize.

What I like to do is rotate the young dogs between my two packs, so that all the dogs are socialized. I found that there was no problem when I mixed a mature dog with a young dog, a mature bitch with her daughter or son or both, a dominant with a submissive dog, a male and a female of about the same age. I had less success when combining brothers, sisters, a female with a female from a different pack or two dominant dogs. Also, I found very difficult to integrate mature dogs brought in from other kennels. In order to introduce new blood into the kennel, a musher sometimes needs to acquire a pup from a different breeder. The best age is between the age of ten and twelve weeks.

A dog is submissive to the dogs stronger than him, but will become dominant to a younger dog. All the dogs in the pack are vying to get a higher position. When the boss dog does his job, the other dogs settle in their places. 

By the time the pups are ten months, I hitch up a team of adult dogs. We go one hundred meters down the trail. At that point, my assistant releases the young dogs. They catch up with the team, run between the adults and imitate the pulling action. After a little while I put them into the team, towards the back, for a short distance. There they can make mistakes like sniffing and marking but they are not in the way of the adults. When they have got used to pulling without distractions, I put them in the middle of the team. They are quicker and more agile but have to learn to pace themselves.