It's good that the inside of his beak seems clear. Pasty material can be thrush or canker so you don't want those.
It can take time for a crop issue to clear up, hopefully he will start to get better. I'd take a look at his poop.
I know you dewormed a while back, but if he doesn't improve, then I would consider deworming again just in case worms are part of the problem.
It can take time for a crop issue to clear up, hopefully he will start to get better. I'd take a look at his poop.
I know you dewormed a while back, but if he doesn't improve, then I would consider deworming again just in case worms are part of the problem.