Rooster Booster died on the gallops this morning while being prepared for the Stan James Christmas Hurdle at Sandown on St Stephen's Day.
“He died of either a haemorrhage or a heart attack. We’re not sure yet,” said trainer Philip Hobbs.
The 11-year-old grey won the 2003 Champion Hurdle and was runner-up to Hardy Eustace the following year.
``At least he died enjoying what he did best,'' said Hobbs.
“He was having a gallop ahead of the Christmas Hurdle when it happened.”
Rooster Booster was runner-up to Harchibald in that race at Kempton last year.