I Have Evidence!

When the pups are about four weeks old, I move them from the whelping crate into the puppy pen. At this age they're starting to toddle around and of course are growing bigger. I start out putting a bed, and mom's food and water. Later I add more.

Puppies are pretty good about not wanting to soil where they sleep. So once they are toddling around, they will usually walk off their bed to potty.

So then it's time to introduce the litter box. The litter boxes I use are the right size, that I can fit two end to end on the opposite side of the pen from the bed.

"Hey, what's this thing?"

*sniff, sniff*

And by the next day I have evidence that they're being used. :)

 Yep, that's what that little dark speck is!