At what concert did Ozzy ozborn bite off a doves head?

Ozzy Osbourne never actually bit the head off a dove during a concert. The incident you may be referring to occurred during a concert in Des Moines, Iowa, on January 20, 1982, when Osbourne bit the head off of a live bat that had been thrown onto the stage by a fan. This incident became one of the most infamous moments in rock history and has been referenced in popular culture numerous times.