Hello everyone, so my baby cockatiel ( a bit less than a month old) started one day to mouth breath. I felt really frightened but a moment later stopped and it was a relief. But since then I noticed that he was weaker than usual and ate a lot less formula so i got him to the vet who gave me anti bacterial pills that i deluded in water and gave him 3 times a day ( a few drops each time). The day after he became more energetic but still didn’t eat as good as before and slept late after ‘bed time’ while crying non stop even when not hungry. Today i felt he was way better ,energy and food wise, but i still gave him a last dose of the medicine i mentioned earlier. Few hours later while he was walking on the ground i noticed that his beak and feet were turning white as blood didn’t flow anymore and he started limping and loosing control of his head while flapping his wings. I was in shock because he was perfectly normal seconds before and i tried desperately to give him a heart massage and to blow gently in his mouth but he died anyway. I can’t describe how sad I am right now and I’m not willing to have birds anymore because of the guilt. But I’m here looking for advice about what could have caused that so i can in my turn help someone to avoid that or to not repeat the same mistake another time if in the far future i changed my mind and felt ready to engage in this very serious responsibility