Lovebird losing feathers under left eye above beak
My pastel blue fischer's lovebird is slightly over a year old and recently the patch under his left eye and above his beak is becoming bald. It had been about a month now and the patch seems to be getting bigger gradually.
The exposed skin looks a bit red and feathers seem to be trying to grow back but i think he scratches them off. We went to the vet twice but she didn't know what it was although she ruled out mites or sharp nail scratching. She gave him some drops to reduce the irritation but that did not seem to help.
I'm worried that he may have some illness but the vet doesn't seem to be able to diagnose what it is. Should I remove all his sand perches and hard surfaces in case he's rubbing his face onto them? I don't know what to do help please thank u