Puppy Behavior

Question
This is such a great site. I have picked out a mixed breed, Maltese and Chihuahua mix, the puppy is currently 7 weeks old and with the breeder, I am suppose to pick him up at 8 weeks.  I've been visiting almost weekly and are noticing some strange behavior in the puppy I picked.  The other 4 puppies in the litter are very playful and he seems to be very withdrawn. Once when the owner opened the Kennel, the other puppies rushed out to greet and he stayed in the Kennel, when the breeder coerced him to come out, he came out but went in the opposite direction. Recently, the other puppies all came up to the Kennel, but he went and laid down with his head away from the others.  When I pick him up he smells my hands and clothes,and makes eye contact, but is not very active. He also seems to isolate himself from the group.  His breeder has kids so I believe he's been exposed to socializing. The breeder administered shots at 6 weeks and treated him for worms. I work eight hours a day, so a mellow puppy may not be bad, but I want a puppy that will be happy to see me when I get home.  Should I consider choosing another puppy?

Answer
A puppy that size (any puppy any size, actually) should not be separated from its dam (mother) and litter mates until 12 weeks of age.  This puppy is already demonstrating strong avoidance behavior, unwillingness to come forward and interact; it might be the "runt" of the litter, the breeder is an IDIOT who should NOT be offering a puppy with this problem for sale, and especially such a young, small breed puppy.  This so-called breeder may have elected to allow his/her dogs to breed in order to make MONEY, s/he is certainly not at all knowledgable and not someone to be trusted.  At eight weeks (the time this moron "breeder" has elected to let his/her puppies go), this puppy will be at the beginning of a genetic fear phase; what you are seeing now (which is HUGELY problematic) will WORSEN.  You are not equipped (because your profession is not dog behavior) to deal with this puppy, nor do you have the time (given the fact that you have to work for a living!)  That puppy cannot be LEFT ALONE for eight hours a day (nor can any puppy, for that matter.)  Find a Maltes or Chihuaua rescue organization with legitimate credentials (not just a group of people calling themselves "rescue").  Adopt an older dog that is already house trained, has been FOSTERED by the rescue organization, and whose temperament is well know, and solid.  You are asking for MISERY here. Take a pass.