Re - my male rats

Question
QUESTION: I have two boys who are about 10 months old. One is shy and doesn't like to be picked up much, and the other is very outgoing and loves to play with me. I don't think either are very aggressive, in fact, I don't even know who is the alfa male. I want to get at least two more baby boy rats, but I'm not sure if it's a good idea. I really don't want them to seriously hurt each other. I get that they have to establish their place in the group, but what if their is blood involved or something worse?

ANSWER: Male rats!!!!!  I LOVE having males and in fact, only keep males now mainly to avoid mammary tumors that, unless you spay your females young, which can be very risky, your females have over 75% chance of developing these nasty tumors, so I buy males. However, males can be tricky too. Sometimes they do awesome in a trio, but I dont suggest keeping intact males if your going to have more than three and even when pubery strikes between 6 and 8 months of age, the harmony of the once happy trio is disrupted and the males start to fight, sometimes till they hurt each other seriously.  My boys did that this time.  They were bred from a very good breeder, but all three boys wanted to have it their way or no way and that wasnt going to fly with each other, so now the sadly live solo ....but they are happy this way. I dont like it one bit, but they made their own  decision.  I do not suggest putting young bucks with older rats, (males)its almost always a pain in the neck.

---------- FOLLOW-UP ----------

QUESTION: Ok, so if I really wanted to bring more rats into my life, I should get only one more and they should be about the same age as the others?
Also, I really want to get a Critter Nation or a Ferret Nation. I like Critter Nation because it has 1/2 bars and they are horizontal. Unfortunately, it doesn't come with an add on, which is a bummer. I would have liked to have three levels. I'm interested in the Ferret Nation as well because it does come in three levels and on www.drsfostersmith.com, there are fleece (I think)pads that fit Ferret Nation's dimensions exactly. If I got Critter Nation, the pads would be slightly off. The only problem I have with Ferret Nation is that the bar spacing is 1 inch. My boys are pretty big, but as I said earlier, if I was ever to get more they might be able to squeeze through. (I like to buy them at 3-4 months of age if I can so that I have them longer.)
P.S. Thanks so much for the info. It's definately appreciated. I can never trust people at the Pet Stores and sometimes websites are false.

Answer
I have a ferret nation. You cant really use at least till the rats are 3 to 4 months old or they can get right out easily.  I love it though.  I am not sure why you want to have a three level Ferret nation. Of course, you can never have too much space and the more space the better, but if your going to have just 3 males at the most, which again, I suggest only that amount unless you neuter them, a two story critter nation or ferret nation is plenty big. Well actually its more like a four story if you consider the two shelves it comes with.  It is taller than me at 63 INCHES. The critter nation and the ferret nation both can house 16 adult rats comfortably.  Have you gone to my site, sandyscrittercity@yahoo.com? Check it out, esp the page titled GETTING STARTED.