Some of these guys do enjoy-belly heat-wich probably does raise thier temp.a little higher.I had some success using a glass tank,a small repti-therm U.T.Heater{these dont get hot enuf to burn}(unless room temp is over 80')-,and terry-cloth-a single layer on tank bottom and another to hide under(washcloth)and ambush prey from/with the addad bonus of not eating wood chips.I dont know what size or how old your snakes are.If they are still juvis I'd try the deli-cup method again with some belly heat.Gosh I sure hope you can get them feeding.I know how frustrating this can be esp.X7 jenni/