A successful breeder or handler understands the critical developmental phases of our canine companions.
Neonatal Period
For the first two weeks of life, a canine neonate is unable to see, hear or thermoregulate. Primarily, the entire neonatal period is devoted to one function; obtaining nutrition by nursing. A normal mother will provide optimal care for her puppies, and attention should be concentrated on making sure that the dam is well nourished and allowed to care for her puppies undisturbed. The most that the owner needs to do is to inspect the puppies once a day for possible illness or accidents. This inspection may lead to secondary benefits. Although we have no direct evidence, experiments with other species (Levine, 1962; Denenberg, 1962) strongly indicate that young animals benefit from the stimulation of handling.
Transition Period
Evidence shows that the transition period is one of profound reorganization of behavior. The most essential change in function is from the neonatal to the adult form of nutrition. Another fundamental change is from the neonatal to the adult form of locomotion. This period starts with the opening of the eyes and ends with the appearance of the startle reaction to sound. The whole period takes less than a week, with the eyes usually opening completely at 13 days and the startle reaction usually appearing at 19.5 days (Scott and Fuller 1974). Smell and taste also begin during the transition period.
Awareness Period
For the 3 days after the transition period, puppies become fully alert and aware of their environment. Qualitative changes to brainwave patterns indicate the onset of active learning.
Socialization Period
In the period of socialization, there are two basic rules for producing a well-balanced and well-adjusted dog.
The first of these is that the ideal time to produce a close social relationship between a puppy and his handler occurs between 6 and 8 weeks of age. This is the optimal time to remove a puppy from the litter. If this is done earlier, especially at 4 weeks or before, the puppy has little opportunity to form normal social relationships with other dogs. It will form close relationships with people but may have difficulty adjusting to its own kind even in mating or caring for puppies. On the other hand, if primary socialization with people is put off to a much later period (the outside limit being about 12 weeks), the social relationships of the puppy with other dogs may be very good, but he will tend to be timid and to lack confidence with people.
The second general rule is that the young dog should be introduced, at least in a preliminary way, to the circumstances in which it will live as an adult, and this should be done before 3 or 4 months of age. The young puppy from 8 to 12 weeks is a highly malleable and adaptable animal, and this is the time to lay the foundation for its future life work (Scott and Fuller 1974).
Juvenile Period
This period begins with the first long excursion away from the den or nest box and ends at sexual maturity.
All the sense organs appear to be fully developed at the outset of the juvenile period. Permanent teeth begin to come in at about 16 weeks of age, and all are usually present by 6 months. Growth curves also begin to flatten out at 16 weeks. The period of rapid growth is over, and the puppy is approximately two-thirds of its adult size. (Scott and Fuller 1974)
The development of motor capacities in this period consists of increases in strength and skill rather than the emergence of new patterns.
Inhibition Period
From 18 to 24 months of age, puppies go through young adulthood. They begin to look like an adult, but still lack the judgment and physiology to make good choices. Impulse control may be lacking, and high-risk behaviors may surface. Towards the end of this period, domesticated dogs go through an important tollgate as they begin to develop inhibition. At 2 years of age, most working dogs are capable of professional capacity.