Your snake is looking good, maybe a little thin, but not the worst I have seen. You could try feeding every other week, that would help out. I can't see much of the set up, but the heat rock worries me, do you have a retrostat or thermostat on it? They can get very hot and possibly burn your snake. If you don't already have them, I would suggest two hides that are tight fitting, one on the hot side and one on the cold side.