Hi taramazing88. You can put greys in there but do it at your own risk. I personally wouldn't recommend it because the screen may be abrasive to his skin and not hold in humidity. Any crickets left within the cage could possibly chew through the mesh (if it's plastic) For keeping in humidity and ventilation (if that is what you are looking for) i would reccoment the exo terra or zoo med cages, the 12x12 is the minimum but i would recommend a 12x18.