Pups breeding

Question
Last week I bought what I thought was 3 females from a breeder.  2 of the girls are sisters from the same Mom and Dad.  The girls are now 4 weeks old. The third baby turned out to be a little boy, and is now 5 weeks old.

I am not able to get the breeder to return my e-mails or phone calls.

My concern is that in all of my research (before I obtained rats as pets), was that females can be ready to reproduce at 5 weeks of age.

Is this true?  If I am not able to return or exchange the male with the breeder, and have to separate him, won't he be lonely?  At what age can he be neutered?  Will he be too old to be put back with the girls once he is neutered?

I have not separated them yet - spent a lot of money on a nice big cage for 3 rats.  I have a little carrier that I can put the little guy in for now, but am very worried about him being lonely, and am not really wanting to purchase a 4th rat - especially since I can not get a hold of the breeder.  I had originally wanted females due to the fact that they do not urine mark as much.  Any advice would be grateful.  Michelle

Answer
Ideally the breeder should not have weaned them and certainly not sold them before 5 weeks of age. To wean at 3 weeks is highly irresponsible and can be very, very bad for the baby, in my opinion. That being said; it's not completely unheard of for females to pop into heat the day they turn 5 weeks old.. however normally a female isn't overly 'into' the idea of boys until 7 to 10 weeks, so you do have a little bit of a grace period.

Either way, separate your boy now to be on the safe side. He will be lonely for awhile, but unless you plan on getting another male, he'll need to stay that way! Males can be neutered as early as their testicles descend, but most vets won't offer it as an option until between 4 and 6 months of age. He will need a minimum of 2 weeks to recover before he can be put back in with his sisters, and the odds are that if you go through proper introduction procedures they won't even mind him being in with him.

Boys are such loves, I don't think you'll be disappointed with your token male.. they do tend to be a little more marky than females, but they make up for it in sheer laziness, size, and the fact that they love to cuddle.

Good luck!