Dogs are den animals by instinct. When your dog is preparing to give birth to a litter, she'll seek out a secluded space where she can nest and deliver the puppies in peace, a place to keep the puppies warm and dry in their early days. You can make her delivery easier by providing her with a nesting area, commonly known as a whelping box.
The Whelping Area
As your dog's due date approaches, she'll look for a space she can use as a nesting area. It will likely be dry, warm and away from the high-traffic areas in your home -- a closet or laundry room, for example. If you don't want her to make herself comfortable or go through a messy delivery on your carpet, you can provide her with a whelping box. This is generally a cardboard box lined with blankets or towels, that your dog can lay in to give birth without feeling exposed. This prevents drafts from making the pups too cold, and gives her the privacy she needs to give birth and care for her litter.