Quote: i tried it both ways, i had faster growth with the rocks over the cornish. however, i do think the cornish over the rock gives larger breasts. but the growth rate was always slow for me. the cornish roosters are a little more agressive, the hens under then always looked "overused". if you can find a breeder who has bred rocks up for growth and meat, i would get a couple roosters from them.
just so im being straight with everyone, it takes years to breed a cornish rock cross like the one you buy. i have looked and looked and never found true white cornish. that cross is not just cornish and rocks, there is some orpington in the mix and probably a few other breeds. the orpington in the mix has happened more over the last few years, to whiten skin and legs for cosmetic reasons.
another little hint, look for smokey colored white rock chicks. the same gene that makes them smokey makes them stay whiter and more appealing to the eye.