European Union countries are stepping up tests on farm birds as the deadly avian flu virus threatens to hit domestic fowl.In Germany, a second test on a farm duck has proved negative after initial tests suggested it might have had the disease. Results from a third, conclusive test are still awaited. In the meantime, precautionary culling continues on the Baltic Sea island of Ruegen where the cases have been found. The lethal H5N1 strain has now also made its first appearance in Slovakia in a wild falcon and a grebe. It takes to eight the total number of EU countries with confirmed cases in wild birds. But cases in domestic birds are likely to shake the poultry industry, which has already been hit by falling sales. France, meanwhile, has reported a suspected outbreak of H5N1 at a turkey farm in the east of the country and is awaiting test results on Friday. It comes after EU officials approved plans by France and the Netherlands to vaccinate millions of birds in specific high-risk regions.