This is Daisy’s whelping box. I found plans for building this box here. Ours is 4′ (48″) square. The “pig rail” around the inside is to keep puppies from getting squashed if she lies up against the walls of the box. When she goes into labor, we will remove the blankets and replace them with disposable puppy pads, much more absorbent than towels (absorbency and disposability are both key features!).
She gets in her box happily when I tell her to, as well as voluntarily. Lucy does too, sometimes. It is located in our study, out of the way of household traffic. She’s been hanging out in here with me a lot for the past few days!