Yes, hold him and pull down on his wattles to get a good look inside his beak for yellow, white mucous or crusty material. The inside of the beak should look clean and not have anything like a build up in it. Smell his breath while you are at it.
If you have a helper that's even better.
Let us know if he has anything inside the beak, this will tell more about how what the next step should be.
I would consider deworming him. If you have a vet that can do a fecal float that would be good, otherwise, you can find Safeguard at TSC. Dose is 0.23ml per pound of weight given orally once a day for 5 days.
