I have never heard of a wild caught rosy that bites. You will have a nice pet for many years to come. Do not fret about the eating. A rosy of that size will eat a hopper mouse about twice a week. Do not worry if it does not eat. It will eat as long as it is healthy. Keep it out of direct sunlight, as it would not take long to heat up and die in the heat. Your hot pad idea on one side of the cage is a good idea. Make sure that the snake can get off of it if he wants to.