Around 100 million birds have been culled across Europe and the US in the past year following the 'worst-ever' outbreak of avian influenza.On the Sky News Daily podcast, Sally Lockwood speaks to poultry farmer Mark Gorton, director of science at the British Trust for Ornithology, James Pearce-Higgins, and Sky's science and technology editor Tom Clarke about how serious the threat is to business, consumers and wildlife.Senior podcast producer: Annie Joyce Podcast producer: Emma Rae Woodhouse Interviews producer: Alys Bowen Editor: Philly Beaumont