Sulphur Crested Cockatoo disease

[sibley]

I have many wild birds that come into my garden feeding and I leave seed and various nibblies out for them. I love watching their antics, whether they are playing or squabbling.
They have become quite used to me now and i'm able to sit amongst them taking photo's. The lorikeets are especially trusting and are easily hand fed.

Recently I have noticed about 6 Sulphur Crested Cockatoo's that have a terrible feather deformity on their heads. I thought it may have been PBFD, but from researching this disease, it seems the feathers on the body are affected, but the birds I have seen have severe feather loss only on their head. Some lose their crest, but others still have theirs. I haven't noticed any beak problem and the very worst affected bird I have seen has lost an eye.

I don't own any birds, so i'm far from a bird expert, but I was wondering if anyone can confirm or deny this is PBFD, or help me identify this horrible disease that these lovely birds have and if anything can be done for them.
I have included some photo's below.

It really is quite distressing to see these magnificent birds reduced to this state.

[Phill]

Aww them poor bugger's. I have no idea..

[vankarhi]

It is hard to say whether it is PBFD without actually having a test done. They don't look too good though do they. If it isn't PBFD maybe they are plucking each other, or maybe they have mites...........although even with mites I would imagine it not just being around their heads.

[judy]

poor guys.