I don't have much experience. I would say though that if he was living in an improper cage than what other husbandry was improper (food, supplementation, lights). These could definitely effect his growth if he wasn't getting what he needed.
Im sure that others will give their...
I have no experience...but i have noticed when i look through craigslist that i will see ads in the pet section for dubia roaches and different feeders for sale.
hopefully someone has experience for you on here :-)