A couple things of note:
1) Wire bottom cages are not at all good for rats. They can develop a condition called bumble foot and your babies can easily fall through of get hurt. Below is a picture of my breeding setup:
This is large cement mixing tubs from Lowes. The construction is cheap pine lumber painted black. Half inch hardware cloth is stapled to the upper section over the tub to keep the rats in.
The rack on the right of the image is 50g or so Sterlite tubs that are modified to hold a water bottle with a dremel and hardware cloth. These are my grow out bins for feeders being raised up and/or future breeders.
2) It is worth the time and effort to source pet quality rats from the beginning. Paying $30 each or more for starting stock may not seem like a deal, but in the long run it's worth it to not have to breed out maternal aggression or other undesireable traits.
3) Unless you're planning on feeding 10+ snakes, you may be better served with buying frozen. Breeding rats is a commitment to my time every week that measures a few hours. I also sell my excess feeders and make money at it, so that helps account for the time too.
Hope it helps you out.
Paul