I'd like to share my opinion about cricket, my uncle used to breed them for his birds (cricket is the best food for twitter type bird and good for their voice). Cannibalism problem is simple, because the cricket source of food is all eaten. To prevent cannibalism, make sure the cricket always have something to eat. Try put out many dry leaf to make sure that the cricket have something to eat. If they can find anything to eat they'll eat each other. What crickets do in their whole life is eat and eat . That's way here in my country, crickets consider as pest.

I upload some photos from local cricket farms. As you can see that box full with dry leaf and also fresh food for the crickets and with so many dry leaf on the box it also provide hiding shade for the cricket. Remember that cricket love dark place. That is box for raising the young cricket into adult cricket.