Tens of thousands of devout Hindus thronged a temple in southern Nepal where thousands of animals and birds were sacrificed this week, amid an outcry from animal rights activists who said the ritual was a cruel and gruesome spectacle.The ceremony, held every five years at the Gadhimai temple in Bara in southern Nepal, is believed to be the largest such mass-slaughter event in the world and animal rights activists have been campaigning to end it for years.About 80 per cent of Nepal’s 30 million…