Please help, I bought my cockatiel two months ago and he has been an absolute beauty since we got him. Today I came home and my partner said he had been having sneezing fits but when I saw him he came straight to me for lots of tickles and climbed all over the cage as usual. He has been eating plenty as normal but I noticed he made a squeak sound on 4 separate occasions this evening while eating and was shaking a little so i put the heating on for him. (I have two thermometers with alarms which go of if it reaches below 20 degrees and the current temp was 26) The last week he has really developed as he had a new cage bought for him last month and he loved it. Before I got him I researched Cockatiels for months and joined this and another forum as well as well as this I have been over pre-cautious about everything I do with him or in the home environment around him. Tonight I covered him at 10pm leaving the front curtains tied back for him and at 10:30 he began to have a sneezing fit, I lifted the cover and he fell off his perch and clung on to the bars lower down. his neck was tilted back and he flapped but landed upside down, his head still locked backwards. I spoke to him calmly and lifted him up and out. He was gasping for breath with his head stiffly locked backwards, his wings were out stretched fully but were completely limp. To me he was having a seizure so I just stroked him and spoke calmly to him,...within 30 seconds he tensed up completely and his head dropped down,...He was Dead! I am Devastated!!!! I have had no chemicals in my home since i got him, no drafts, temperature always ok, he eats seed and vegetables and fruit and I feel I have done nothing wrong. He had been molting feathers over the last couple of weeks but only one or two every day for a week then it stopped. looking at his cage the is brown fluid (possibly blood) on his mirror where he had been sneezing or coughing just before he died. Have I killed him or could he have had a disease? also his leg band is violet which means 2015 born but it also means 2003 and the serial number is 8TGF 03 P (03 is horizontal). I have read that 03 means the year born? is this correct in the UK? could he have been 13 and not 10 months? I feel so so so sad.