Way too smart!

I've been taking the puppies out of the side door without the doggie door so that I can clean up and disinfect their pen, and the smart little boogers go out the door and straight to the back door with the doggie door and let themselves inside.  This would be great if they would all use the rest room first!  I say that, but there have only been 2 accidents out of 8 puppies over the last 3 days of them doing this.  They love to roam the kitchen, crawl under the chaise lounge, and chase the poodle, and when they go back in their pens they are very upset!