Just to clarify, mice and rat breeding is NOT the same thing. Mice and rats both have different requirements as well as personalities/behavior and you have to deal with both accordingly. If you treat mice like you would rats, they will get stressed out and will eat their young. Rats, on the other hand, do better when separated singly into their own, small(5-10 gallon) cage or large critter keeper. It keeps them in closer proximity to their babies, and even new, inexperienced moms do better this way.

What are you feeding the rats? They need a good quality diet containing grains, fruits, nuts, and a good protein source such as a HIGH quality dog food(Wellness Senior, Nutro Senior, etc). Whatever dog food you get, it needs to have a protein % of less than 20%, or the rats will come down with protein sensitivity issues(scabbies underneath chin, on sides and scratching alot). If you do a source for rat food mix here, I have written a good recipe for a mix that will provide everything your rats will need. In addition, you need a good source of lab blocks to provide the essential nutrients that the mix may not provide. Mazuri, Purina or Harlan Teklad. You can do a search around the internet and find a good source who sells them.

Mother rats with babies are VERY protective, and you should not handle her or the babies excessively. Always remove her before messing with the babies or you may get a nasty bite(rat holds on and bites to the bone-NOT a warning bite). She needs alot of good protein while she is nursing such as cooked chicken bones, meaty table scraps, hardboiled(with shell on) or scrambled eggs, etc.

And please, if you don't want babies, and insist on keeping all 3 together, get the females spayed or get the males neutered. OR the best situation would be to get the female another FEMALE friend(after your female has weaned her litter, of course), and keep them separated at ALL TIMES.

Hope this has helped a bit and if you need any other assistance, just let us know.