He and harry were on there broom and Hedwig gets hit with the killing curse
BEcause he gets hit by a stupefying spell from a death eater also because j.k Rowling is an ideot
She takes a killing curse squarely in the beginning of the seventh book.
hegwig dies while trying to save harry during their flight in the beginning of part 1 Dobby dies while transporting Luna, harry, ron, and heromine to the beach to get a way from Bellatrix and she...
Chapter 4 pg 55 is sadly when Snowy fluffy owl HEDWIG dies
she gets shot by a killing curse