Wijk en Aalburg - Chicken has been inside a chicken shed for 12 hours since today. Agriculture Minister Carola Schouten is introducing a national obligation to keep all companies that keep commercial poultry in order to prevent the spread of bird flu. The confinement obligation came into effect at 12 noon, the ministry reports. A highly contagious variant of bird flu (H5), which leads to serious illness or death in birds, was found at a poultry farm in Zeewolde.