The socialisation period in puppy development — from 3-12 weeks — is critical for adult temperament, with inadequate socialisation being a major cause of fear-based behaviour problems.
Puppy socialisation welfare has lifelong consequences: a dog inadequately socialised during the critical sensitive period faces a lifetime of anxiety, fear responses, and potential behavioural problems that significantly reduce quality of life. Fear is not merely a behavioural inconvenience — it is a welfare state involving genuine suffering. Inadequately socialised dogs are more likely to be relinquished, more difficult to handle veterinarily, and more likely to bite. The window for preventing these problems through positive exposure during the sensitive period is short and cannot be recovered. Puppy class attendance, varied exposure to environments and people, and positive veterinary handling during the first weeks of life are welfare investments with returns measured in years.