My parrotlet Lemon has been shaking, fluffed up and lethargic for a month now. We have seen two vets, she has completed a course of antibiotics and given vitamin treatment (a super shot and sent home with calcium and Sunshine Factor). She is still eating, preening, playing and sleeping as normal. She just spends most of her day on the bottom of her cage and sleeps a lot. Don't think it's heavy metal poisoning or fatty liver. Any other suggestions of what it could be? I am sick if pumping the vet with money to be told nothing is wrong. Thank you.