Well... When you put a boy and a girl together... babies are generally the end result. I think we went over that in health class, probably 5th grade or earlier?
Why did you breed the rat if your snake won't eat frozen? Those rats will quickly outgrow your snake by the time they're about 7-8 weeks old(your snake definitely doesn't need a medium/large rat, they're fine on weaned or smalls).
Might want to just stick with getting one prey item a week from the store... Less wasteful.