Sorry but it is a nonsense - the roaches need high protein foods.Stop feeding them high protein foods. They only require about 18% protein in their diet. Your jacking their uric acid levels and this could be causing a problem. However, it seems like you might have some husbandry problems there as they don't seem to be eating much at all. How are you keeping them?
I agree with Peter.I see the same thing with my lobster feeder colony. Without heat they aren't very big eaters compared with some others.