When will they start breeding?

I found a guy on craigslist that picked up 2 rats and they gave birth to 13 babies. Well he wanted them gone so he was giving them away. He said they were just weened. When i got their to pick them up they were almost small-med rats. I can still use them. But I dont want to turn around in 2 weeks and have more babies then i can handle. I just want to know what im getting into.
I dont want to turn this into a permanent breeding situation due to the fact that im growing my ASF colonies.

3 - 4 months is when they begin to breed. In my experience anyway. When they hit that between size of small/medium watch out and separate by sex. Any males that have developed noticeable testicles are separated asap. Watch for signs of dominant grooming, rough play and flat out mounting. :rofl:

They can breed as young as 6 weeks...not healthy for them...
If you don't want them to breed, seperate them by 6 weeks.

You can see the difference(ie, the baggage) at 2-3 weeks of age.

Technically they can breed as young as 5 weeks old, but they shouldn't be bred until they are at least 3 months old.

I personally never had rats breed until 7 weeks. Some have though!

Look I'm new so really can't say much and will probably get blasted for saying this. Rats can become preg as early as six weeks. The ones Im breeding are about 2.5 months old. They're are about 8-9 weeks old now. They became preg about 6 weeks.

But as bokuza said earlier watch for those signs. Overall the horse play begins and goes for awhile. It will stop..... then after 3-5 days if the horse play doesn't start back up again then chances are preggo is their eggo.

Thats great. I dont have enough tubs for the ones that I have now lol. Well looks like I will have enough food for a while.