As usual, too many assumptions are being made of the OPs brief post. It's a dependent upon what a dog is used to. If they are outside dogs (yes, as absolutely crazy as that may seem to most, there ARE outside only pets still here in this country), then it would not be an issue crating them in the bed of the truck, assuming adequate cover and ventilation. But yes, if they are spoiled house dogs (as mine is), then the dog wouldn't like it much. Of course, they would survive (as I would when my AC goes out on my car), but they would just be uncomfortable for a bit.