Even with one mom and three children in the house, the humans can be too busy and too distracted apparently to scratch a dog's back in a timely manner. Chief and Bella have found a way to get that itch on their own. And the result is pretty darn hilarious.
I believe Chief invented this trick and Bella now imitates it. They lay on their back - preferably on grass or a rough textured carpet - and then they wiggle. They go back and forth and wiggle around like a worm on a hook. Only they're on the floor. They especially seem to enjoy scratching their back hips or rear this way.
The first couple of times you wonder if they're having a fit or a seizure. You get kind of worried until you see the goofy, happy smile on their little canine face. Then the laughter starts. With entertainment like this, we may never scratch their back again.