new 1 yr old chihuahua puppies

Question
my husband and i just saved two puppies from going to the pound, the previous owners brought them and all their things over and everything was great. we have a brother and sister as soon as the previous owners left the girl who is very protective over the boy became very aggressive and tries to bite us, once we get the boy away from her he is fine very lovable i really don't want to separate them the are really attached to each other, please help ASAP please!!!!

Answer
Google "littermate syndrome" and you will find information on how keeping litter mates together can be somewhat challenging.  My advice is to enroll each dog, separately, in a positive training, or clicker training class, so that you can establish some communication with them individually.  To learn more about your dog's possessiveness, Google "resource guarding" - there'a a great little book on it, too, called "Mine! A Practical Guide to Resource Guarding in Dogs" by Jean Donaldson.  Mostly it's devoted to dogs that guard food, but there are still helpful hints for other types of guarding behavior.  These dogs are NOT puppies, they are adult dogs, so you will have to treat them as such.  That means they are beyond the socialization age, but they can still be worked with in terms of training, and some behavior modification.  You do want to give them a few weeks to get used to you, so that they don't feel frightened, especially the female.  Each time the boy is out of sight, try feeding the female some small chicken or turkey bits.  When he's brought back into the room, stop feeding.  Once she seems to be looking forward to him leaving, in order to get her turkey, then you can try feeding them little bits of turkey simultaneously, being very careful not to drop any and cause a food fight.
If you continue to have trouble, try contacting a trainer who can come help you at home - there are force free trainers on the Truly Dog Friendly web site listings.