For some reason i don’t have the privilege to reply to your post so I made a new one. If you want to the vet and they have found nothing wrong with your bird I would suggest a couple things if your bird is having breathing problems. I have six different species of birds and the conure is without a doubt the most sensitive to anything and can start sneezing and breathing harder over the slightest thing. If again the vet has found nothing and your bird is still having breathing problems it has to be something in the air in your home. On top of that being upset because the other bird died and the broken feather that was bleeding. Is your home very hot? The first thing I thought of after reading your post is there must be something that is causing the bird the breath hard if the vet found nothing wrong. My conure is very sensitive to all aerosols, deodorant, perfume , air fresheners, laundry detergents, dryer sheets, even if the smell from the dryer sheets come through the air conditioner vent from my basement it can bother him. I’m am beyond sure that your conures breathing problems are from something that I’d around the house! I’m sure he still isn’t bleeding but it will take sometime for his loneliness to get better he’s just going to need that companionship with you! Please let me know how things turn out and if you find anything like a cleaning product or perfume or any chemical that could be causing this. Also was your bird having breathing problems while at the vet /avian doctor or just at home?