“All the puppies”
It must be awesome having a dog that knows its own bedtime. What’s even better is that this dog doesn’t even force its owners to get into bed when it’s time for its bedtime. The OP’s dad had conditioned their dogs to sleep at 9:00 PM every night by exclaiming, “it’s time for all the puppies in all the world to go to bed.” Cute!
As the dog grew older, you only had to say “all the puppies,” and it knew that it was time to hit the hay. If the owner ever forgot to say this, the dog instinctively knew that that 9:00 was time for shut-eye.