About Populating the DateField Value For Fields with auto_now_add

In order to set a value for a DateField field with auto_now_add attribute, you'll have to update the entry with the QuerySet's update() method after creating it:

for author in Author.objects.all():
    person = Person.objects.create(
        first_name=author.first_name,
        last_name=author.last_name,
    )
    Person.objects.filter(pk=person.pk).update(
        created_at=author.created_at,
    )