When do you know its the last puppy?

It's impossible to know for sure when a litter of puppies is complete. The only way to be certain is to consult with a veterinarian. They can perform a physical exam and potentially an ultrasound to determine if there are any remaining puppies.

Here's why it's difficult to know:

* Individual dogs have different litter sizes: Some breeds naturally have larger litters than others.

* Puppies can be hidden: A mother dog might hide a small or weak puppy, especially if it's her first litter.

* Labor can be irregular: Labor can be long and drawn out, with puppies being born several hours apart. It's not uncommon for a puppy to be born after the mother seems to be done giving birth.

If you're concerned that the litter might not be complete, it's always best to contact a veterinarian. They will be able to provide the most accurate information and guidance.