My Sun Conure Mango

Question
My Sun conure will be 2 in June. He was hand fed by a local breeder. I got him when he was weaned. About three weeks ago I traded him for another bird at a local bird fair.  I immediately regretted my decision.  I got him back after only 4 days.  I am concerned about his behavior.  Since then he has completely changed.  He will not talk now & his vocal sounds has changed.  He is hesitant to come to me.  He stays in his tidy seed box alot now and will not sleep in his tent.  He hangs on the side of his cage to sleep at night.  He no longer holds his bowels until morning but defecates all over the side of the cage through the night. He will not take a treat from me.  He loved fruit, dried mango, nuts and lots of human food. He did go through his first heavy molt.  His feathers are a different color now though, more orange than yellow now.  In a picture I have of him, the feathers are more yellow than orange. He also chewed a thousand holes in my t shirt He moves his head around and ignores me.   He lifts his tail up and moves it side to side.  I did take him to an avian vet.  He had a yeast infection.  I gave him his antibiotics and some medicine for yeast for 10 days.  I think he is well now. Could he have changed because he has reached sexual maturity? My concern is that the temporary owner may have switched birds.  I cannot believe this could happen in just 4 days.  Any info will be greatly appreciated.

Answer
---I'd be highly suspicious too.  Unfortunately there is nothing you can do to prove this since you didn't have a well bird visit to establish him or her with your own personal vet

 I'm sorry, but all you can do is try to love this one and adjust the behaviors with that love

Here's a good guideline and 'how to'  www.4animalcare.org/birds