mine like lettuce, but the favorite is dried mealworms which i give them in the evening, ive only got to shake the bag and they come running, 
my lisht sussex is fab at catching flies.Love ham and bacon fat!!! Go absolutely nuts - but they also get the vege scraps to dig around in, dried corn and are provided with an endless supply of pellets to help themselves to. And I often see them chasing a fly or bug or something ...