It all really depends really on the BCI. But you should be able to feed him on either 2 large or 2 jumbo rats every 2 weeks or you could switch over to small rabbits. rabbits would be more cost effective for most people. When i had my large burm he was eating 3 large rats every 2 weeks untill i switched him to rabbits. i was paying $18 for the 3 rats and $10 for the rabbit.