Answer:
Basically, breeding with rats is the same as breeding with mice. You just get a male and female rat and put them together. Leave them together for a while. After the mating takes place, separate them if you wish. But, you MUST remove the male before the babies are born or he may cannibalise (eat) them. If you would like to, you can put another female (who recently had babies) with the mother to be a foster mother if the real mother needs to sleep or something like that. When the babies are about 4 months old, separate them according to their gender or you might end up with unexpected litters of rats. Good luck with your breeding!!!