We had a dog once who was not interested in her puppies. We would put her in the box with them and she would reluctantly let them nurse and she would give them a cursory lick here and there. Then I guess as soon as she felt relieved, out of the box she would go. She was of the right age and lived inside with us, but had no maternal instincts. All the puppies were fine and went to good homes. My mother kept one of them.