1. Puppies are born not fully developed. Their eyes are sealed shut because they need to finish the maturation process. Even at eight weeks when these puppies will go to the ophthalmologist their eyes are not fully mature. Puppy eyes tend to open around two weeks.
2. Their ears are also closed at birth and they can not hear until their ears open somewhere about three weeks.
3. Some breeds are more mature at birth than others, many being able to walk right from birth. Havanese tend not to be able to get up on their feet until sometime between two and four weeks.
4. Puppies are born not able to regulate their own body temperature. For this reason they have to be kept in a temperature regulated room until they are about four weeks. This makes makes them extremely vulnerable to bacteria and viruses. The herpes virus is one of the main threats to a puppy because the body temperature must be over 100 degrees to kill off this virus. The average adult dog body temperature is around 101 degrees.
