Hi, I only want to add that here in France vets suggest to use this cream (it contains salicylic acid):
Véto Products offers Dermaflon healing and cleansing cream for horses, dogs, cats, horses, etc. in 30 g
www.produits-veto.com
It is used to promote the healing of wounds especially when the healing process is hindered by the presence of necrotic tissue, clots, debris, etc.
Here in France it is highly suggested because it is able to "dissolve"/remove necrotic tissue.
We used it for the first time in 2014 when we rescued Nerone, one of my brother's pigeons. She had a necrotic area on her chest and the vet suspected that someone intentionally burned her....
In case there are necrotic areas you could look for a cream having a composition similar to it:
Malic acid 0,4 g, Benzoic acid 0,02 g, Salicylic acid 0,006 g, Propylene glycol 1,7 g, Methyl parahydroxybenzoate. 0,0005 g, Propyl parahydroxybenzoate. 0.01 g, Excipient qs 100 g.
In case the bird will not eat pellet (which is enriched with vitamins, amino acids and minerals as SilverFeral explained) you can add to his drinking water a complete vitamin supplement containing vitamins, amino acids and trace elements.
Please keep us updated.