This article is from the Chihuahua Breed FAQ, by firstname.lastname@example.org (Melinda 'Bob' Casino) with numerous contributions by others.
Generally speaking, no. However, there are many exceptions and many
people have written me telling me of just how sociable their
Chihuahua is with other breeds. So I'm inclined to say that
Chihuahuas can be very curious and friendly towards other dogs.
Chis are very sociable with their own kind. So several Chihuahuas can
be quite happy living in the same household. That includes two or
more males sharing the same house.