Behavioral scientists have identified the period from 4 to 14 weeks as the most important window of time for a puppy's social development. (whole-dog-journal.com)
Thyroid deficiencies in pregnancy during important windows of development in the brain have been proven to be a problem for the baby. (babygaga.com)
Because the first 3 months of a puppy's life are when sociability outweighs fear, this is the most important window of opportunity for puppies to adapt to new people, animals and experiences. (sbhumanesociety.org)