I'm a new bearded dragon owner, and I think he's going into brumation already. He hadn't been eating as much as he used to, taking naps during the day, and has been spending much more time under his hide then he used to. Is this brumation? I'll add in a picture of my setup just in case the setup is a problem.
Hi there, it looks like he's an adult already, or a sub adult ? if he's new to you and in a different environment, that can cause them to hide for a while or become less active. Just give it some time.