Cockroaches in my worm farm

yes they are and ants and all sorts of greebys. All of these things work together to break down food. Try sprinkling a handful of lime into a half litre of water and wash over your food scraps in the farm. Then try to bury your food waste in a corner and cover with the worm castings and bedding that they have already made so as to keep attractive odor to other pest away.