Seeking to reassure people that chicken is safe to eat, companies that raise chickens said recently they will test every flock for bird flu before the birds are slaughtered, according to the Associated Press. Companies that account for more than 90 percent of the nearly 10 billion chickens produced in 2005 in the U.S. have signed up for the testing program and said it expects more to follow, according to the National Chicken Council, a trade group that represents producers. Consumption of chicken in the U.S. has held steady despite worries about a bird flu strain that has infected millions of birds throughout Asia and parts of Europe and has killed 74 people. The plan is for 11 birds to be tested from each chicken flock or farm. The council said the average flock has 55,000 to 60,000 chickens and that there are an estimated 150,000 flocks produced year. That would mean more than 1.6 million chickens would be tested. The virulent form of bird flu in Asia has not been found in the U.S. and is only now spreading into Eastern Europe. Authorities there say that cooking kills the virus. Health officials in the U.S. say it is safe to eat poultry that is properly handled and cooked. Bird flu can spread to chickens, ducks, turkeys and other domestic birds through direct contact with infected waterfowl or other poultry, or contact with contaminated cages, egg crates, water or feed, according to the department. Even the dirt or manure on shoes, clothing or tires can be tracked from one farm to another and transmit the virus. In bird flu outbreaks among poultry, anywhere from 90 percent to 100 percent of the birds can die from infection. In outbreaks, poultry farms typically are quarantined and the birds slaughtered.