How soon can you identify "bad" temperament in young rats?

aldebono- Thanks for your comments in both threads! I'm learning so much here.
I must admit that the temperament and health of the three rats I started with is mostly disappointing... Although one of the two remaining rats is as you described, outgoing and not scared / thrashing, etc. the other is still quite shy (but workable). Both are now showing signs of a possible URI and I've ordered antibiotics online to treat them with and keep on hand. This is kind of frustrating as I did my best to pick out apparently "healthy" rats. I can only hope that the two I end up adopting are truely healthy and maybe less prone to URIs.

I'm thinking that when i do start to look for breeding stock to start a real colony, I may need to try and buy at a reptile expo (if the animals are healthy) or find a local feeder breeder that I can buy from who has healthy stock. At this point, I'm not trusting pet store feeders, unless I can breed out the myco / URI susceptibility within a couple generations... Is this possible coming from weak stock though?

I'm half way considering asking the lady if I can adopt some females from her as well (although my husband would probably not be on board) and keep them separate from the males so that I will be able to breed from them within the next year or so (females are virtually impossible to come by in my area). I'm still unsure on what to do. If I'm having this many problems with the three rats I have now, do I really want to upgrade to having, like, 5-6 within the next month?

This whole rat keeping / breeding thing is turning out to be more complex than I thought it would. *sigh*

Thanks again for your help and advice! I may start another thread as this one is going OT.

RI/Myco is very treatable through antibiotics, I used Tylan which you can buy at the Tractor Supply Co.

When I lived in Florida, my rats were kept outside unless it froze at night, below 50 degrees, they would be covered and supplied newspaper to shred and make nests. My first winter I had a lot of myco flair ups and a few losses, but the second winter, none of my lines that had been with me through the previous year had flair ups. Rats that I had added during the summer needed to be treated. So either of these situations could have happened, either they were a very happy established colony (stress free) after being there over a year, a natural selection happened that the most prone rats died off and left me with healthier stock, or they were just more prepared for the second winter and their bodies adjusted easier.
Stress brings their immune system down and that is why you are starting to see a myco flair up.

I also learned from a fellow rat enthusiast here that when she was breeding, the rats with the broader heads were less likely to get RI.

Basically, everything can be bred out. But, with poor stock, you may have your work cut out for you.

Thanks for the info, i purchased baytril and amoxycillin (sp?) online and will be treating with them when they arrive (hopefully next week).
I've heard that stress can cause flareups with it as well, so it'll be nice to have the antibiotics on hand for any new arrivals.

I'll look up the Tylan, it's likely a better deal than where I got the other antibiotics from.

Thanks for the info!

Once you get enough experience, you can actually pick out good temperaments from bad temperaments from a very early age. As aldebono said, even with minimal handling you can breed well tempered rats. I'm basically starting over now from when I was breeding strictly pet/show rats, but at that time I had lines that had the most fabulous personalities you could even want. Very little phased them, they were bold, friendly, personable. I was extremely strict with my selections. Now, I'm not breeding pet/show any more, but I do want rats that i don't have to fight to handle. I don't want to be attached, so I really don't handle them much, except to clean bins and check up on everyone. I don't have the fabulous personalities I had as a pet/show breeders, but I am careful with my selections to pick out the best personalities. In time you can make improvements, you just need to be strict and not get overly attached to one characteristic at the expense of another.