Whelping and Puppy Pen See the Whelping and Puppy Raising section. Dog boxes should be large enough for the animal to stretch out in and should have dry bedding and adequate ventilation. Dog boxes should be solid, have easily operable latches and locking devices, and be securely attached to the truck for the dogs' safety. Boxes should not be open or vented in the back of the truck because the vacuum created behind the truck can suck in exhaust fumes. The door should be a minimum of 14 by 17 inches with a vent of 9 by 11 inches.
Some mushers believe that dogs are more comfortable when doubled up in larger boxes.
If you wish to do this, be sure to match compatible companions. If you carry your dogs in an open pickup truck bed, it is important to secure them so they cannot fall or jump overboard. In cold weather, wood or bedding material should be provided so they don't sit on cold metal. Airline crates are good if available and are preferable in summer because they provide more ventilation than standard dog boxes. When traveling, dogs should be taken out several times a day.