Chocolate lab puppy not barking at all

Question
Well me and my wife got two chocolate lab puppies and they're about 3 or 4 month old. Both females same family Sasha and Hena. We noticed that Hena does not bark at all. Even when they play together only Sasha makes any kind of noise like barking,growling. Is there something wrong with Hena?

Answer
If you are concerned that Hena may suffer from some physiological problem, make an appointment with your VETERINARIAN.  I am not a veterinarian and I can't see anything from here.

It is not always the best choice to take two puppies (especially same sex) from the same parentage or litter.  Temperament can be so similar as to make it difficult for normal social structure to be acquired by the puppies as they mature: in other words, being very much alike in temperament can make a struggle for "power" between them into a serious problem.  At 3 to 4 months, barking an alarm (as a dog would if someone knocked) can't be expected, dogs are generally not mature enough, but vocalization during play (play growl), whining, barking in excitement, are all normal.  Sasha may be the stronger of the two (in terms of temperament) and this may be inhibiting Hena's vocalization.  It also may be inhibiting her reaction to other things in the household.  If Hena is given a clean bill of health by your veterinarian, this lack of vocalization might actually indicate that Hena is falling into line behind Sasha (whom you would most likely already perceive as being more outgoing, vocal, "demanding", etc.)  Regardless of this: YOU need to bond with both puppies rather than allow them to bond primarily to each other.  This means you must interact, separately, with each puppy with positive reinforcement training, walks off your property on a daily basis to meet/greet others, spending several hours a day between the two of them.  In this way, they will develop a primary bond to you, both will gain more confidence, they will learn independently how to react to their environment(s) and you will have much more control over their day to day behaviors with one another.

Read Dr. Ian Dunbar's "Before and After Getting Your Puppy..." and go to his website:
http://www.youtube.com/watch?v=Hv38ornzzuQ