I also wanted to mention that if male rats live alone, they usually don't have much of an idea on how to go about the whole "breeding" thing. Sad as it is, they need a buddy to "practice" on, and it is very important to their well-being to have another rat of the same sex(or spayed member of opposite sex) around. You won't have a very good breeder if he is kept alone.

Also, if my rats can FLING themselves out of the bathtub when wet, then I am absolutely positive that if that lid is not secure, those teensy babies WILL get out eventually. A secured screen top will prevent escape as well as provide the adequate ventilation that is required for their absolute health. And yes, water bottles left inside cages will get holes chewed in them. The duct tape will also get torn to shreds. I also hope that isn't pine bedding. Babies, as well as adult rats, are incredibly susceptible to respiratory infections and ailments. If that is pine, and they start to have red stains(porphyrin) around their eyes and noses( or dried on their fur-its rust colored), they must be taken off of it. If babies are gasping to breathe, that means they aren't nursing and growing.

As for breeding, the females should NOT be bred until they are at LEAST 4.5-5 months old. This will help ensure that you don't have females dying from babies being stuck in the birth canal because the female's pelvic canal isn't done growing. Males can be bred at around 3-4 months if they are big enough.

I know many of ya'll believe that these rats are JUST a food source for your snakes and should only be kept at the minimum living conditions to maintain life and breeding. But you also have to remember that how you keep your rats and how they are fed directly influences your snake's health. If these animals aren't fed correctly, and are only fed dog food or a "mix" from the pet store, then your snakes and other carnivorous reptiles that eat them will start to show signs of it. By keeping them on appropriate bedding, housing and feeding appropriate foods, they will provide you with huge litters of robust, healthy babies that don't have breathing problems and aren't getting eaten by the mother rats. Mother rats who are overcrowded(or who are even kept with other rats while birthing, nursing, rearing) will cannibalize their young or may not even accept them at all, resulting in a lost litter and money lost on your end.

Here is a good page on nutrition, housing and general care: http://www.rattiusmaximus.com/ratcare.htm

Anyway, I hoped that helped a bit, and if you have any other questions, just ask