I am "snake-sitting" my son's rosy & likely will be for the next several months. During the summer & fall, he usually ate weekly with an occasional skip of a week. For the past couple of months, he has not even shown interest in the mice I've tried to feed him. I thought perhaps it was because he was cold so I got a larger pad for the bottom of the tank (it also sticks better) & a second light as he was spending most of his time curled up under one of the bask rocks. I also got a second lamp and now the temp in the tank is closer to 80° at one end. He is more active now but tonight he again showed no interest in the mouse. He has been raised on thawed, killed mice so I don't think that is the issue. He seems healthy & active otherwise & his eyes aren't clouded as though he's getting ready to shed. The snake is in a 20 gallon tank, the humidity is close to zero, the substrate is shavings which I recently changed. Should I be concerned & does anyone have any suggestions.