We hear from a lot of breeders who are upset because their puppies sleep in the litter in the toilet area instead of the crates. If you want your puppies to sleep in the crate and not the shavings the easiest way to encourage this is for the crate to offer thermal relief for the puppy - the crate should be a more comfortable temperature for the puppy than the shavings.
Sounds easy enough, but what that thermal relief will be is HUGELY different from breed to breed. The “thermoneutral zone” is the temperature at which a dog can maintain his body temperature without expending energy to increase heat production or heat loss, and (sit down for this) it ranges from 68°F to 86°F for dogs. Literally, there is almost a 20° difference between the way different dogs experience the same exact temperature.
Jane Messineo Lindquist (Killion) is the director of "Puppy Culture: The Powerful First Twelve Weeks That Can Shape Your Puppies' Future" as well as the author of "When Pigs Fly: Training Success With Impossible Dogs."