The reason I ask is if he came from a Pet store, he is probably majorily stressed out and not only needs time to adjust, but should probably see a vet ASAP to be checked for worms and parasites. Rare is the beardie that comes from a Pet Store that is not loaded with both.
Chain Pet Store beardies have usually been shipped to a warehouse, transfered by truck to a store location, set in a new enviroment that is neither temp controled or cleaned along with other dragons that have been there and already stress having parasites and worms that only get worse with sub optimal care. A terrible formula for a baby dragon and usually not with good outcomes.
If a private breeder with a good reputation, chances are he just needs some quiet adjustment time, especially if he was shipped.
But still I would get a fecal after 2 weeks just to rule out he was so stressed changing homes he did get a coccidia bloom.
Check all your husbandry issues.... temps right? light the kind he needs? foods? Substrate?
Its always easier on them if you know what they have had and spent the majority of their live on so far, and thats usually not what they have in a pet store. IF you know the breeder, call and ask them, that's the best bet for making the change as less stressful to them as you can.