The critical socialization window from 3-12 weeks profoundly shapes adult dog behavior, making this period the single most important time for welfare-positive early experiences.
Inadequate early socialization is a leading cause of adult dog behavior problems including fear, aggression, and anxiety - major welfare concerns for both dogs and humans. The AVSAB recommends that puppy socialization begin before 14 weeks - the disease risk of poor socialization exceeds the infectious disease risk of early social exposure with appropriate precautions. Breeders bear primary responsibility for early socialization from weeks 3-8, with new owners continuing the process.