I forgot about time - that the beak reflects conditions at the time it was being formed. The part near his body does look better, so maybe it will grow out. Do you know how fast a macaw beak grows?
Gus is picky with food. He was on Harrison's at the rescuer's, then the rescue switched him to Roudybush, then his human fed him colored zupreem, then I got him some zupreem naturals. He has eaten them all, in fact he prefers them to veggies and most foods. I bought some Harrison's with pepper which is what his first rescuer (who works at the vet) says he ate and as soon as he finishes the last of the supreme he can start having that. What kind of supplements do you give Tino? I read that in humans, iron deficiency can cause peeling nails and biotin, a B vitamin, can strengthen hair and nails in humans so maybe it's good for hair and feathers.
Thanks for the explanation of what he's doing, it fits with what I observe.
I don't know if you have the same products as in Europe, but I give Tino 2 different supplements. One is a liquid, which I should think would be available to you
Versele-Laga Muta-Vit Liquid fældnings-middel | zooplus.dk
The liquid is vitamins given in the water to birds moulting.
The other is thishttp://xn--gjeknas-q1a.dk/da/vitaminer-og-mineraler/507-vi-spu-min-1-kg.html, which is a powder based vitamin/mineral mix for every day use. The powder gets sprinkled over his pellets. As the pellets have a porous surface, the powder stick to the pellets quite well