Naturalist Chris Packham has led a crowd of protesters in slamming Pret A Manger. He vowed never to set foot in one of the chain’s cafes until it fulfils a chicken welfare promise it made eight years ago and has since broken. Packham said: I am absolutely furious at Pret for breaking their promise to chickens. Factory farming has broken the chicken. Bred to grow so fast that they can barely walk, scrabbling around in their own waste, broken bones and deformities… The life of a fast-growing chicken is hell. It’s a horror story dressed up as a lunch menu. It’s absolutely…