I'm at 8 weeks of raising 15 x-rocks. I've butchered 6 over the past two weeks, picking the biggest birds. I've been waiting for the remaining birds to get bigger an planned on butchering today or tomorrow but the birds just don't seem to be getting bigger. I've been feeding both 18 and 20% starter since they were born. I know others talk about higher protein, but the birds were growing really good, but now I'm not sure. I don't want to go to higher protein, unless I must. Should I just go ahead an butcher them without worrying about their size? And, I don't really know their exact weight, so I'm just going on apperances.