Green Cheek Conure chest feathers?

by Dana
(Canada)

Digby is 6 years old, he is my noisy baby. I moved out for 2 years and couldn't take him with me so he stayed at home with my parents. Over year ago when I moved back in I noticed his beautiful chest feathers are no longer there, in their place are soft grey down-like feathers.

I thought it might have been stress but it's been over year and it's still the same. I dont see him picking at them or anything, besides the occasional preening. The rest of his feathers are beautiful except for a few fluffy ones on his upper back. It's the chest that has me worried though, because its completely grey and fluffy.

I find it hard to believe its a extra long moult. But I have no clue what the problem is...
I feed him fresh water and pellets daily, wash the dishs daily. Give him seeds as a treat, he gets a fresh fruit and veggie mix every day along with the occasional piece of meat and egg. I know birds are generally lactose intollerant but Digby is 6 and ever since I got him, he has been obsessed with yogurt. He has had no ill side effects and just adores it.

I give him a bath every couple of days, and he has a lot of playtime out of his cage daily.
His behaviour didn't really change since I came home, I did however notice he has definately beome a one person bird sticking to me like glue. He really doesn't like men and will puff up and try to attack any man who enters the house unless I show him it's okay and take him from my hand and put him on the male. Other then that he is still very playfull and very talkative.

Any help to what might be going on with his feathers would be much appreciated.