Bedding for a litter of puppies serves many purposes. Bedding should provide comfort for mom and babies. It must absorb urine and other body fluids to keep everyone dry, and the bedding should provide some level of body-heat retention. The "best" bedding for a litter of pups depends on age, size and occasional extra needs.
Start With a Box
Before selecting bedding, consider the bed itself. Most pups will live in a whelping box until it can see and walk and explore, and will gravitate to it for most of the eight weeks or more that they're in group as a litter. The box size will vary according to the size of the breeds involved, but they should be tall enough to keep the pups confined for several weeks. You can add an exercise pen or use pet gates or suitable barricades to contain the curious babies. The floor of the whelping box should be solid and waterproof. If the box is not waterproof, find a bottom liner that is rubber, like a floor mat or carpet runner.
Thinking Inside the Box
Many breeders use shredded newspaper to line whelping boxes, but others prefer towels and blankets, wood shavings, or even sand. You should consider all options and select materials that match needs at specific times during your puppy-rearing experience. Shredded newspaper is probably the most common bedding used by breeders. It provides cover, but it doesn't limit the puppies' mobility. Newspaper is available and inexpensive, but the ink can rub off on the puppies. If you live near a printing press, try to get end rolls, which are clean but not cut. Call to find out when these are available, because they are free of charge and free of ink.
Some breeders prefer used towels, blankets and sheets. These items are warm and comfortable for the dogs, but be sure the pups are old enough to maneuver through these items before using them -- a trapped puppy could be injured or suffocate. This might be your bedding of choice if the whelping box is in a drafty area. The cloth items require laundering, which adds a chore to your list. Some breeders like wood shavings because they absorb the fluids and help with odor control, and many like puppy pads that are available at pet supply stores. The pads can get expensive, and an alternative is purchasing paper bed pads from a human health supply store.
When the puppies near 4 weeks of age, they will start to get up on their legs and attempt to walk. During this period, the puppies will need secure footing to help the balance. Rubber padding under paper or cloth bedding helps the pups progress. At this time, some breeders introduce the topic of house-training and select a section of the whelping box to be used for this purpose. Some line the potty area with a different material than the sleeping area of the box. Sand, wood chips or even flat-laid newspaper are good choices. Healthy dogs won't sleep in a soiled area, and many puppies learn quickly where to pee and poo. Regardless of what kind of bedding you choose, be prepared to change it several times each day.