Cockatoo health

Question
the lump in question is slightly to the right of his breast bone.. he is in a cage about 40 by 24.. and I have just started giving him Roudy Bush..... before I had him... he was malnourished.... but his coat is improving.. and by the way it is to his right.... thanks
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-----Question-----
My Cockatoo has recently acquired a large lump on his chest.  It at times is soft and has loose skin on it, and at other times it is quite hard but firm.  He has recently gone through stress as I did rescue him due to him not being taken care of.  He recently plucked out feathers and became emaciated before I got him.. He is now looking healthier however the previous owner says this lump is new. Do you know what it could be?
-----Answer-----
Is this lump just below his head/jaw on his right (to your left as you're looking at him straight on) ?

Also, what sort of cage is he in?  How long is he out of it (and is he out of it every day?)

What is he being fed?  

Answer
This location could indicate a crop problem, especially with a history of malnourishment.
The cage size is very good! Getting him out of it for at least two hours a day every day is important too. We make sure our rescues are out of cage for at least 6 hours every day and actually outside whenever the temps are above 60 degrees. Of course, clipped wings are an absolute must if a bird is taken outdoors even for a minute.

Depending on when this 'lump' appears most prominent, it could be food being retained in the crop or moving slowly out of it.  The question is - is it too slowly? Is there impaction? Malformation? Only an avian vet performing a hands on exam can tell.
 This pretty important to have done, no matter what you have to go through to make it happen.

Take a look at us and our own set up here:  www.geocities.com/animalrelief_info  

   Let me know how this goes - ok?  You can contact me here or through my site.
 By the way - keep up the good work!