Most people interested in dogs have heard about ‘socialization periods’…..periods during which dogs learn about other dogs, other species, and new physical and social environments. Was there a role for these periods in the reactivity that characterizes the behavior of the lovely Missy Rose?
Newer data in all species suggest that we would do better to think of these periods as ‘sensitive periods’, which imply risk assessment. A ‘sensitive period’ is the period when animals may best benefit from exposure to certain stimuli, and where, if deprived of such exposure, there is an increased risk of developing problems attendant with the stimulus. In other words, when animals are neurodevelopmentally able to respond to stimuli, they will benefit from exposure of which they will avail themselves, if it is available. Lacking exposure, behavioral problems associated with the omission could develop.
So, let’s consider only the effect of being adopted at ~6 weeks for the lovely Missy Rose. A 2011 study showed that for 70 adult dogs who, as puppies, had been separated from their dam and litter from 30-40 days (5-6 weeks) with 70 adult dogs who, as puppies, had not been separated until after 8 weeks, early age of separation was a significant predictor for excessive barking, fearfulness on walks, reactivity to noises, toy possessiveness, food passiveness and attention-seeking behavior. Early adopted dogs were also more at risk for destructive behavior than were those who had been permitted to stay with their litter through 8 weeks. By itself, her age of first adoption could have contributed greatly to the lovely Missy Rose’s difficult to manage reactivity.
Whatever other forces are contributing to the lovely Missy Rose’s behavioral path (stay tuned), the lesson is clear for dogs in general. If puppies are kept with their families (at least the siblings and dam) in their home environment through 8 weeks of age, the risk of a series of the most common behavioral reasons dogs are relinquished or euthanized is reduced. This finding has profound implications for puppy mills who are often allowed by state laws to sell and transport puppies by 7 weeks of age. Clearly, such laws are not in the dogs’ best interests (nor are puppy mills). Anyone selling a puppy should be guarantee that their pups have at least this small advantage of growing into their sensitive periods within a protected familial environment that gives their brains the best chance of normal age-associated development.
 Pierantoni L, Albertini M, Pirrone F. Prevalence of owner-reported behaviours in dogs separated from the litter at two different ages. Vet Rec 2011;169;468 doi: 10.1136/vr.d4967.