Dubias rule......
The breeding cycle is about a month as long as they are fed correctly, have a decent humidity (mine are at about 50%, and thriving), and have a good temperature range.
Colony Size:
You'll need something like 15-30 adult female roaches per chameleon if you are using them as a staple food item. The male to female ratio should be something like 1 male for every 4 to 5 females. If you want to boost a colony so you can feed out of it right away just pop like 1000 to 2000 mixed roaches into it at the start. Otherwise you will have to wait a couple months before the colony matures and starts really producing for you.
Cage and Temperature:
I have my colony set up in a Tupperware container (14"tall x 36" long x 14" Deep) with a heat-pad underneath one side of the tube. The heat pad is hooked up to a thermostat to maintain a temperature of 95 degrees about 1 inch off the floor. The egg crates are stacked side buy side vertically above the heat pad, this makes it easier for the roaches to get out of the heat if they need to cooldown . I also put some card board between each egg crate to prevent them from collapsing into each other and killing any roaches. The food dishes are on the other side of the tube.
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Sorry image is so crude I thru it together in the minute I have)
Food:
I use Collard Greens, Carrots, and a dry cricket/roach food. I also provide water crystals just in case they need more water than the carrots can provide. Any food placed should be inspected for mold every day, fruits and veggies should be replaced every other day.
DO NOT feed them fish flakes or a high protein diet, this can make them unhealthy for your chameleons.
Cleaning:
You should spot clean out uneaten food regularly, clean completely once a month taking out all the roach poo (which doesn't sell much at all), and examine the egg crates also. If the egg crates are soiled bad replace them with new ones (Egg crates for me usually last 2 months).
Egg crates:
I came up with a method for deciding how many egg crates to use. If anyone has a better idea for this let me know.
1 egg crate for every 100 adult roaches
1 egg crate for every 200 1" roaches
1 egg crate for every 500 1/2" roaches
1 egg crate for every 1000 1/4 " roaches
(note: I typed this up quickly and didn't have time to proofread it like I normally do, so there might be some spelling/grammar errors. I'll try to fix it later when I get home)