British supermarkets reassured customers on Wednesday that the latest bird flu outbreak would not lead to a Christmas turkey shortage, as the government ordered the slaughter of thousands more birds. Poultry on four new sites were ordered destroyed as a precaution to prevent the spread of the virulent H5N1 strain, after it was discovered Sunday on a farm with about 5,000 turkeys, 1,000 ducks and 500 geese. A total of 24,000 turkeys were being slaughtered on the five sites, all connected to the Gressingham Foods company, according to the Department of Environment, Food and Rural Affairs, or DEFRA. It said it was investigating whether H5N1 had spread between the sites. Officials said no disease had been detected yet at the four new sites, all located within a restricted zone around the infected farm at Redgrave, 160 kilometers northeast of London.