We needed the pen.

It was a big day for the puppies. They got toys and began playing with them, and they found a way to get in and out of their whelping box. 

The box was only six inches tall, but they are not quite three inches off of the ground when standing. But once one got over the wall, the rest soon followed. And then they began coming and going as they pleased.

We put up two temporary walls as soon as one puppy made it out, but tonight we simply put the bigger box together. Now they have a big box with high walls. We will need to raise the walls a few inches before this is all over with.