So I live in Colorado my adult Vail chameleon hasn't eaten anything to my knowledge for over 3 weeks. It's winter time and it's getting down to 10 F. at night and I read somewhere that someones chameleon didn't eat for a month in the winter, and then on a warm day he started eating again. I just made him a DIY larger cage about a month and a half ago and he hasn't eaten anything since then except for 1 cricket and 2 super worms. Has anyone seen anything like this? His basking spot is at about 80 F. And he's 2½ years old. He's surprisingly hasn't died and still drinks everyday. He spends a good hour a day also roaming his cage. I think I'm just now after a month and a half seeing the results of him not eating. His eyes are starting to sink in and I'm going to try to force feed him soon. Any advice?
I wouldn't say "force feed" so much as "trick feed". Is he one of the rare nice chams? If not, you're in luck. What I do is get them intentionally mad... so much so that they gape. Then it's just a matter of plopping a choice feeder into that mouth and checking the result. If he chews, win. If he spits it out... I'd probably take him to the vet.
My concern wouldn't so much be not eating as much as lack of supplementation - If he isn't eating, unless you happen to be mixing calcium and a multi vit into his water..?
^ that would be my other suggestion.
While climate does effect their eating habits, after about 2-3 weeks they start going through the stored nutrients in the body. Most species that go that long without eating go into brumation to slow their metabolism enough to not do this. However, you say he's still active and drinking daily, so this is not the case.
I do want to say though, the majority of my experience comes from Panthers. I do own a veiled female but I've only had her about 6 months and she was a rescue. I am also not a vet and my overall advice to you would be:
No one knows your cham like you. If you feel something is wrong, go to the vet before it becomes a serious issue.
Best wishes