High protein feed & lots of it. We butchered at 8 weeks old. Hens were 5-6# & roo's 8-10 #'s. Can't even fathom how they can get that big so fast. You do have to take their feed up for night or they will eat themselves to death, no jokingGuess I didn't think of it that way. You wouldn't want to free range to keep the weight on I'd think? And my chickens do get out about everyday. Do they eat a certain diet too?Red, they are so nasty looking. Their belly's are dragging on the ground. Feathers all rubbed off on their underside. It might be different if they freeranged a bit, but just kept in a coop all the time is a disgusting process.