The socialisation period between three and twelve weeks of age is the most welfare-critical phase of a dog's life. Experiences — and absences of experience — during this window shape behaviour and welfare for the dog's entire lifetime.
Puppy socialisation is perhaps the single most impactful factor in determining the lifetime welfare of a companion dog. A well-socialised puppy that becomes a confident adult dog is more likely to be kept and enjoyed by its owner — undersocialised, fearful dogs are more likely to be surrendered to rescue. The puppy farm and pet shop supply chain systematically disrupts socialisation through early removal and transport stress. Choosing puppies from breeders who actively manage the socialisation of their litters, and investing in early puppy classes, are the most effective early welfare interventions.