I agree with Doug on the temps. He may be going into shed again, in which case it would not be uncommon for him to go off feed. You can also cut back on feeding twice a week and try once every 7 to 10 days. I had a Honduran go nearly a year without eating and he is still around and eating well. While that's not ideal, I say it to let you know that 2 or 3 weeks isn't a big deal yet.

Good Luck!
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Thanks!

Joe Exposito