Puppy barking from separation anxiety

Question
QUESTION: Our cockapoo is 4 months old and we got her 3 weeks ago. She is in a large pen alone for most of the day, but we leave plenty of toys, water, food, and we take her out for walks in mornings and evenings and play with her to release energy.  I started keeping her in one room of the house (baby gated) recently, but she barks and whines continually everytime I leave the room, sometimes for a few minutes, sometimes up to 15.  

She does not bark or whine for more than 2 minutes in the mornings when I leave for work as I think she is used to it.

I tried ignoring it, but that hasn't changed her barking. How can we train her to stop barking every time we leave the room/are not around her?

Thanks so much for your help.

ANSWER: Try filling a small Kong with peanut butter and giving it to her.  Sne may be too busy licking it out to bark.  

This sounds to me like a case of poor early socialization.  A dog that was never left by itself before 12 weeks, may be slow to accept it.  The period between 6-12 weeks is a dangerous time.  One sniff where a sick dog relieved itself in the last 6 months can bring on parvo or another life threatening disease.  Fail to expose it to strangers, including men, women, children, noise, etc. and you could end up with a misfit you can't take out in public.  They also need continuing contact with other dogs, but it must be limited to ones you know are getting good care.  Be sure and let the breeder you got the puppy from about the problem.  Many breeders have no idea how important the 6-12 week period is.

---------- FOLLOW-UP ----------

QUESTION: Thanks for your advice - will definitely get a kong.

We got her from a pet store (i know, shame on us) so we know that she was alone at night before 12 weeks.  Additionally, on walks, she meets other dogs and many people - she absolutely loves the attention and gets very excited. We live in a city so there are always noises and people about.  Do you think that poor early socialization is still the problem?

I have been reading a lot and people suggest walking in and out of the room often to let her know it's normal, but ignore her each time. Is there any more positive or negative enforcement on top of that to let her know that (1) barking is not acceptable when  I leave and (2) i will always come back?  Thank you so much again.

Answer
I know much more about preventing problems than fixing them.  The walking in and out of the room sounds good.  Try to avoid ever letting her out of the crate when she is barking.  Make her quiet down before opening the crate.  

And yes, I still blame early socialization.  You can improve on such problems, but it isn't quick and easy.