I had 3 large storage tubs, one full of mature mealworms, and that was only enough for treats for my 20+ chickens. Mealworms are easy to raise but so many get eaten so quickly- using them as a feed source is impractical. They also go dormant when it gets cool out.
I knew someone who had a 3 trashcan system (full sized garbage cans). He was able to feed his small backyard flock, I think 4-6 chickens. You'd have to have an entire building or room set up, with heat, to raise enough to feed 20-100 chickens as their sole source of food.
The chickens literally gobble them down so quickly. Someone else wrote that a chick can eat 50 per minute and an adult chicken can eat 50 per second. That sounds about right to me. They are gone in a flash, with the chickens wanting more! Another problem is making sure that all the chickens get their fair share. If you are feeding in a group, the dominant chickens eat all the worms before the slower, submissive chickens have a chance. They will fight over them.
If there was a way to feed a large flock mealworms as a primary protein source, I would be doing it.