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.
So if you have a 75° room, and you have a Newfoundland litter, you need to put ice packs in the crates to reinforce sleeping in them. If you have a Chinese Crested, you need a fluffy warm bed, maybe with a heated disc under it. There is no one right answer, there is only watching to see if the behavior you want is increasing or decreasing.
By the way, this thermoneutral zone concept is important to maternal behavior, as well. The breakout behavior you want to see is the puppies sleeping piled up and close to their mother, with mom comfortable and relaxed - she may be panting, but not restlessly getting up.
If your puppies are flung all over the box like drunks and mom is distressed and panting and can’t settle down, you probably need to try to lower the temperature a bit. You never want to chill your puppies as that can be fatal, but if your litter is strung out and mom is distressed, GRADUALLY lower the temperature in the room (no drafts!) and see if that helps.
If the puppies are in a pile and close to mom and OTHERWISE HEALTHY but crying and unable to settle, the room MIGHT be too cold. Experiment with tweaking the heat in the room or adding an additional heat source such as a bed buddy, nestled around the little in a half circle or a snuggle disc under the hospital pad next to mom. I usually will try the bed buddy first and if that quiets them down then I know the room is a tad cool and I will raise the heat a little, but not so much that they move away from mom, which is stressful for her.
This is true of literally everything. Are toys or food more reinforcing? Is social interaction a reinforcer? Is exploring a reinforcer? Is interaction with a novel object a reinforcer? You cannot answer any of these questions except with reference to how the puppies react. And the answer will often depend on environmental factors and change from day to day and hour to hour. Having a breed mentor is a good way to start, because it will give you clues about what might be successful. But in the end you have to rely on observation to know if in fact you’ve got it right for this particular puppy/litter.
This Leonberger litter would not calm down until the breeder resorted to turning a fan on them. This is 100% correct for this breed but could be fatal in a different breed...watch for the right breakout behavior and make no assumptions about what "should" be the correct temperature for your puppies comfort!
I’ll close this by saying that this concept also explains and would eliminate so many arguments about “what’s right.” Dog people are nothing if not of strong opinions, and they are very quick to proclaim what does and does not work based on their limited lens. There are certainly overriding principles but the details will come down to observation. So 90% of the arguments are between two people who are both right, under the right circumstances. Hope this gets you thinking and observing.
Read more about the thermoneutral zone: https://www.extension.purdue.edu/extmedia/va/va-16-w.pdf
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."