My rats health

Question
I have four male rats and they are all brothers, they are a little less than five months old and have a big cage and I  have had them ever since they were babies so they are well tamed and trained and get along well. But lately one of my rats have been acting strange and getting left out, he has also started going nuts and running around the cage crazily causing things to nock over and also causing him to go into shock for 10 minutes or so afterwards. I'm really starting to get worried about this problem and I am now scared for his health as now I am thinking he needs to be removed from the cage, but I just can't split them up. If you could please give me some advice?

Answer
This is not normal behavior.  I can't say for certain, but there is a good chance he is ill and in pain.  I had a female rat that one day went into a frenzy in her cage, viciously knocking over stuff in the cage and running around in circles.  It appeared she was really angry.  She didn't hurt her sister luckily.  After about 10 minutes of this, she went and sat in the corner of the cage for a long time.  The next day, she was back to normal, eating, drinking and playing as always.  

I don't know for sure what caused her frenzy but I did notice later that her stools were mushy so I concluded that her tummy must have hurt from diarrhea.  I know for a fact that this behavior almost always means pain.

Since you say this behavior has been going on "lately", I assume several days or weeks.  That would lead me to believe something is seriously wrong.  I hope that you have a good vet with experience treating rats and I would not hesitate a moment longer to take him in.  If you need a referal to a good vet, I can locate one for you if you give me the city and state you are in (if it's a small town, I need a major close city name).

I pray he is ok.  Please write back and let me know.