New series. Jimmy Doherty heads to Sicily, where a vast network of tunnels leads to a subterranean salt-processing plant. Kate Quilton looks at free range hens, and is surprised to learn that most chicks on British farms have their beaks trimmed at birth. In the Netherlands, she visits a new cutting-edge farm designed using the latest scientific advances in hen welfare. Plus, in Scotland, Matt Tebbutt makes a surprising discovery about the origins of haggis, and then faces the ordeal of delivering some unwelcome news to an unsuspecting audience.