The secret to keeping roaches (and) having them breed like...well,...Roaches!, is to keep them clean, warm and well ventilated.
Ventilation is crucial to prevent moisture buildup. Moisture is a haven for nasty fungus and bacteria and lots of dead roaches.
Use the largest bin/tub you can find 90-100 litre capacity minimum. Your looking for max floor space, not height.
Using some kind of tool, cut most of the lid area away, leaving a few inches all round.
Flyscreen can be either stretched across the tub Beneath the lid, Or 'hot-welded' to the plastic lid on the outside using a soldering iron or heated flathead screwdriver.
A coating of vaseline (petroleum jelly * messy) or teflon paint, several inches wide around the tubs inner rim will prevent escapes. Likewise, a ring around the outside of the tub will prevent 'undesirable' common cockroaches from infesting the colony.
A stack of egg crate from your local market, each layer separated by flat cardboard and the lot held together with elastic bands, providesa place for roaches to live.
A chinese or similar containe inside the tub will be used for staples (dry food)
This can be dry dog food, fish food, rodent pellets/blocks, spirulina powder etc, whatever you use or a mix of all. Keep this full, cleaning only every so often when most becomes 'powderised.'
Moisture. Fresh whole carrots can be left on the tub floor, as often as required, only as many as the colony consumes as they will rot if not eaten.
Gutloading. Roaches will consume anything, and like other insects need to be kept hydrated and gutloaded for the reptiles benefit. The carrots are the main hydration, but Fresh greens like bukchoy can be added and will be consumed.
Caution: Moisture is a killer and makes roaches stink! Be sparing with WET food. If using wet food, ensure the colony is of sufficient size to rapidly consume wet food.
Half an orange is great for hydration also.
Cleaning. If kept in this manner, roach poo looks like dry fine granules, depending on the colony size, this matter can buildup fast becoming an inch thick on the tub floor.
Prevent this by cleaning atleast once a week.
A Spare TUB.
A spare tub of the same dimensions is handy for cleaning day! This too will be painted/smeared with vaseline or teflon.
Simply pickup the colonys 'hotel' (egg crate stack) and without shaking or disturbing them, place in the spare tub. 90% will remain in the hotel making cleaning easier.
transfer the dry food tub, carrot to the spare tub.
Now you have lots of roach poo and some live roaches in the bottom. scrape or tip, everything to one end of the tub.
Spare Egg crate. Now a spare egg crate will come in handy. Place this in the dirt tub on the side you cleared. Keep the tubs clear end slightly tilted up (shove something under it) and wait a few minutes. The last of the roaches will hide isidethe eggcrate layer and you can now transfer them to the spare tub also.
Now you just have roach poo! This is extremly great garde fertiliser, So dont waste it!
Roses love it! Wash the tub with hot soapy water. Dry thouroughly and repaint/smear if required! The clean tub is now your spare. Switch lids!
Your Done!
Notes: Roaches in big numbers will consume food rapidly. Occasional protein , for example, the dead mouse/rat your snake or frog didnt eat can be left on the roach tub floor and will be completely consumed leaving nothing but tiny skull next day, just like those domestid beetles museums use to clean specimans.
Be aware that the more roaches you have, the better they will do this. Dont leave a large rat if you only have a few roaches.
Baby roaches? Roaches 'give birth' to an egg sac called an 'oothica' which is about the size of a pill/capsule. From this the baby roaches, a perfect copy of adults, emerge.
Babys are easily visible and you wont miss them.
Babys will hide with the adults in the eggcrate hotel but will also tend to hide among the dry food. A few loose toilet roll cores will provide a place for babys to gather where the are more easily separated.
Sorting Roaches. You can make life easier when sorting roaches by size, again using that spare tub! This time a plastic bucket 0.99c at walmart comes to the rescue as a roach seive. Yes seive!
Drill 1/4 inch holes all over the bucket base and paint its inner rim with teflon/vaseline.
Place the bucket over the empty spare tub (holding it above the floor) and tip those toilet roll/saranwrap cores out into the bucket. Big roaches stay put, babys, smaller than the holes you drilled, fall through into the spare tub, ready to dust and feed.