I am wondering if you could give me some advise?  I am considering getting a rat terrier and I am worried about introducing it to my 3 yr old yorkie.  She gets along well with all of the other dogs my other family memebers have(6 in all).  How do I introduce them to each other and can I keep them in the same crate?  Bella(the yorkie) is totally crate trained and I have an extra large crate for her room enough for 2 dogs until the new dog gets bigger then I thought I would get a bigger crate.  I would like to be able to keep them together so they have companionship during the day.  My sister keeps her 2 yorkies in the same cage and I thought that was a good idea.   Any suggestions? 

Thanks Amy

Bella is the only other dog in the house, but my parents have 3 yorkies and my sisiter has 2 yorkies and a basinji.  We only see them when we go home to visit.  We would make more trips home so that all the dogs can get to know each other when the rat terrier is a puppy.  Thank you for the advice about the crates.  I never even thought about the fact they could end up fighting while in there.