My dubias don't seem to be reproducing

[Ghost Mouse]

So, I have a small bin of dubia roaches. I would like them to breed but they don't seem to be doing so. I don't see many babies in there. I have twice now seen ejected oothecas and do not know why. Let me describe how I keep them, and hopefully you will have some advice...

The bin is medium sized. It has gray sides and a lock on lid. I put a little mesh panel in the lid and it takes up a little less than half the lid. They seem to like digging so I have given them relatively deep substrate, a mix of the substrate I use in my terrariums plus a wee bit of aspen shavings mixed in. They also have an egg carton divided in two halves, one that I tip up to crawl on vertically and the other that I turned over so they could be under it. There's also a flat piece of cardboard that I keep upright which they really like to climb behind. 

They have mouse block always available and every other day or so I put veg in there- usually carrots, lettuce, cabbage, and/or celery. I mist the bin regularly and the soil is moist but not wet. Their habitat is right by the space heater I use in the room. 

[Randomjoe]

what temps do you keep the room they're in? I keep my dubia dry and feed fresh fruit or veggies along with dry food twice a week. The room i keep them in has a space heater and never gets below 75f with highs of 80f in the winter and sometimes up to 85 in the summer. Also how big is your colony now? Maybe there just enough yet to notice the difference in colony expansion? 

[Ghost Mouse]

The room is between 70 and 80, I have to keep it warm for my dart frogs. It can sometimes be a bit warmer in the summer. The colony has maybe 40 or 50 individuals? Not too sure.