My Chihuahua,Dakota,had this problem.The breeder we got her from said she was constantly tormented,which is why she was trying to find her a home as quickly as possible.This constant torment made her fearful,especially of other chihuahuas.It quickly turned to dog aggression.We have managed to rehab her by socializing her with calm,friendly dogs her size.It's taken her 3 years to get over the fear and aggression,she was 7 months old when we got her and her age made it harder to correct.

Is their any possibility that Kasey has had a bad experience with a small dog?Or that he wasn't socialized properly with small dogs?

I would suggest continuing the socialization attempts with calm dogs who wont try to force him to play.Praise him if he attempts to interact with the other dog in a friendly way.And at first i would advise keeping the other dog or both of them leashed.Maybe even walking the dogs together.With persistence he will eventually realize he has nothing to fear.Best of Luck

Dakota answered on 8/10/11. Helpful? / 0