Behavior after death of a cage mate

Question
Yesterday, my youngest male rat, Chjimichanga passed away. He had two other cage mates, Rad and Rod for the past 1 1/2 years. To make a long story short, my boys aren't acting the same since his death. They are not eating or coming to the front of the cage like they use to. I'm hoping that they are just depressed because of the lost of Chjimi but I'm scared that it's something more. I definitely see that Rod misses Chjimi since he tries to pick fights with Rad. Honestly, I don't know what to do.. My boys are almost 2 years old, and I don't want to bring a baby boy rat in and have him not have his cage mates if they pass. I do though want my boys to be happy.

Answer
Rats certainly do grieve, and since the death of their friend was only a short time ago they will need some time to get over it.  Usually this kind of depression doesn't last much longer than a week, so if they are still acting strangely after that time or you notice any serious symptoms such as excessive sneezing, weight loss, or listlessness you should take them in to the vet.

 In this case, since your two rats are both the same age and are both older I wouldn't recommend putting another rat in with them.  It would be better to wait until they pass on before getting new rats.

 Well I'm sorry to hear about your loss and I hope your other boys feel better soon!