So, I recently got a 10-month male cockatiel, which is very happy and has very healthy feathers.
He has very good relationship with me, often climbs me and lowers his head for petting and scratching. He also has normal relationship with my female cockatiel: They are just keeping a little distance from each other, but don't fight.
My cockatiels are not in a cage. They are free in their own room with lots of food, drinking water, and bathing water.
Anyway. A few days after I purchased the male cockatiel, I noticed something strange when he was preening: he has very little feathers on his body under his wings. I didn't check his body feathers when I was in the shop, as he had quite healthy feathers everywhere else.
So, I watched him carefully for over a week, to make sure that he does not pluck his feathers. I also noticed that there are no plucked feathers on the floor; at least nothing beyond what's usually left from preening.
Is there a reason to worry? Should I show my cockatiel to an avian vet?