Chickens are the most populous bird on the planet. There are 23 billion of them at any given time - that's ten times more than any other bird. It's by far the fastest growing meat product but pound for pound the price of chicken has fallen sharply. How has this happened?

This farm is at the forefront of a technology revolution that has drastically changed chicken farming. It's run by David Speller who's pioneered the use of CCTV and CO2 monitors in chicken sheds. Along with his own farm, he works as a consultant overseeing the raising of around 3 million chickens in the UK.