I've been using mostly mealworms, which (despite one grain mite) I keep feeding freshly cut up, from the fridge.
Frozen crickets do not seem to be popular with my picky ants.
I tried fruitflies but some colonies just killed them and threw them out as trash, plus the flies crawled everywhere.
I'm reluctantly considering roaches. Because I'm thinking of getting some other small insectivores, I've been pondering small roaches, maybe even very small roaches like little Kenyans (because they are small isopod-sized and I already have isopods).
How do you pre-kill them? I have enough squick issues with beheading mealworms. Fridge then hammer?
Anyone kept little Kenyans as feeders?