[MindieRose]

As a mother of a baby in diapers, and a mother of Diesel, aka Nasty Boy, I can honestly say a well fed dog will still go after a nasty diaper. They are dogs, they like stinky things. Not saying this pup was well cared for or not. Since it was only 6 weeks old, they probably just got it and most people take care of a new puppy, just because its new. Usually they start neglecting it when it becomes not so new anymore.
I am thinking, if the baby was indeed left in the swing overnight because of colic, and obviously everyone in the house was too lazy to care for it, he had probably been in a messy diaper all night.
How anyone could not hear the screams is beyond me. If he wasnt screaming, I would wonder if he had sustained some sort of injury before that or if he was severely dehydrated and too tired to cry.