I wanted to try my hand at Cornish Xs this year and was wondering if any of you just feed them broiler feed with no antibiotics/vitamins. Last year I raised some Dixie Rainbows and they were fed just a straight broiler feed with nothing extra added in. I'd like to do the same with the Cornish Xs. I was told that the Cornish Xs need the antibiotics/vitamins added to their feed because of the problems they can encounter (ex. leg problems). I want my food (meat chickens) au natural as they can be. Do you find this true?