The puppy socialisation period (3-14 weeks) is the most critical developmental window for welfare, with inadequate socialisation causing lifelong fear, anxiety and aggression.
Inadequate socialisation is the leading cause of lifelong welfare problems in dogs including fear aggression, phobias and anxiety disorders. These welfare harms are largely preventable through deliberate exposure to diverse people, environments, sounds and animals during the critical period. The welfare cost of missed socialisation is borne by dogs for their entire lives and is extremely difficult to remediate through later training.