How are you measuring the temperatures? If you're using a stick on thermometer, your temps can be off by up to 20 degrees. Ideally, beardies like a basking spot of 100-110 degrees, so he may be too chilly. If you haven't already, you can go to Walmart and get a digital thermometer with a temperature probe to measure his temps. They are only about $10. That will give you a good idea of what his temps are. If he's too cold or too hot, it could be affecting his health.