Quoted from : Scaly Face in BudgiesKnemidocoptes occurs mostly in older or sick animals that have a weaker immune system. Lesions to look for include scaling, crusting, and grayish lesions on the skin around the beak, eyes, legs, and feet. The mites burrow into the skin leaving large tunnels resulting in the characteristic honeycomb lesion.
In severe cases the beak will start to grow malformed and it might become hard for the bird to breath. Also, the legs and feet will also become malformed and the bird will become lame. Swollen nail beds and misshaped nails can also occur.
Oh, god that describes his feet. But i was told it was from him being in the nest. I don't see an of the 'honeycombs' though his nails and toes are deformed and twisted and some are missing. If it was that causing his messed up feet you'd think that it'd be on his face severly, too, right? And that his beak's be overgrown? His beak seems the perfect length