Flooded tubs can happen. Some of the high dollar systems have drains in them. First tub rack I made used metal mixing tubs. I drilled weep holes 4" up. An the little buggers pulled the valve. I lost some pinks (30 ish) but that was it. I use more water bottles then water systems. The grow out racks use the water systems. They have 40 or so in each tub. Breeding tubs don't need a five gallon bucket. Worried about flooding a tub? Drill some holes an cover then with cheap metal flashing (step is thick an cheap). Water will go around an out the holes. An the rats can't/wont eat the metal. You could use 1/4" wire also.
Was at a pet shop in DE yesterday. They had five 3'x5' tanks with feeders. The breeder tubs where Sterilite boot boxes on shelving. You can start small on the cheap or go BIG.
ARS Caging, Professional Caging for Professional Breeders. Reptile Breeding Systems and Rodent Breeding Systems: ARS Caging
Check face book an the like for snake or rodent groups near you. Snake groups will have a few backyard prey breeders. Rodent groups raise pets. Don't type about feeding them to your other pet
Good luck!