A number of studies done to analyze the general digestibility of food for humans; raw, cooked and dehydrated, raw food has been found to be about 90% digestible, dehydrated food over 80% digestible, and cooked food has been shown to be about 60%.
Clinical trials on the input/output of a dogs and cats eating dehydrated food has not been done, or published in a Scientific journal. The actual digestibility may differ between humans, dogs and cats, and is also dependent on the health of specific individual, their gut flora and so on.
However, the general principle applies that, less heat = less denaturing = more recognizable by the body = more digestible
For sensitive dogs who have issues digesting a new diet, it can be helpful to hydrate the food with slightly hotter water (be sure to cool it sufficiently before serving) to help break down the ingredients a little more, until their digestive tract has had time to adjust. You can also switch between recipes to see if that helps; our Limited Ingredient Dehydrated Diets all tend to be a slightly finer consistency (with Limited Chicken being particularly smooth).