At this stage of life you're probably ok. Typically a RIR will use a 22% or so protein ration, where as you go with an 18% for CX broilers to slow their weight gain and give them time for bone to develop. Red Broilers/Red Rangers are slower growing birds, which means you can start them on a higher protein diet. If it were me, I'd probably look for a starter around 20% protein. In about 3 weeks you should be able to tell who's who. Broiler and starter generally have about the same level of calcium, where layer has about 4X as much. That said, you can move everyone to a broiler ration at the 4 week mark until you're certain who's who. I generally transition to layer a point of lay or about 24 weeks or so. I also give them plenty of grit free choice and add oyster shell free choice around 20 weeks.
