Thanks again for all of your input and sharing your experiences guys!

Last night (before I checked the forum) I went to my local store again and they happened to have a male that was approximately the same size as my male pup. I bought him and introduced them last night and all went well. He's shy, but seems to be sociable and non aggressive and has cute markings and larger eyes as a plus.

Based on your advice, I will let him settle in for a few days then go ahead and introduce both of them before this time next week (making them about 6 - 6.5 weeks old). I think I will still introduce on neutral territory, but will then move them all into a thoroughly cleaned and de-scented cage if all goes well. I will definitely take your advice about the vanilla extract too.

Satomi- Your story about the male with the intestines is probably the most horrifying thing I've ever read rat-wise. Did you gas the poor guy?

Angela- Yes, I'm hoping for good temperament with both sexes, but my lines are unknown (pet shop) and I've heard you can't tell aggression until they are mature at around 8 months or so... Since I am waiting to breed anyway, I guess I can eliminate any of the males that show signs at that point.

Sorraia- Thanks, I will do slow introductions I think, unless things go really well on their first play date.. If I have any doubts, will do multiple dates before setting them up together.

MrLang- If all of them survive, etc. I will end up with 4 males who will be housed together. My first two are probably not going to be used as breeders unless they have stellar health from now on (had some sneezing / Myco issues when I first got them, one in particular). Not sure about the health of the new guy either, so out of 4 I may end up only using 1 or 2 to breed.