I gave up on my mouse project last year, that was a disgusting disaster. Never again XD
My roaches always have dry cat food available, not crushed. They are also provided a bowl of water gel. They get fresh fruits or veggies at least twice a week. They also get an occasional sugary snack, maybe twice a year I'll throw a piece of leftover cake in there or something similar. They also get any table scraps I deem somewhat nutritious (wheat bread toast, salad leftovers, steamed veggies, rice, etc). I've also thrown in flake fish food, old turtle stick food, and other old grain-based or freeze dried pet food items.
Also, I like to feed my animals roaches that have just shed. They seem to digest them better when they don't have hardened wings or exoskeleton.