I've had a much different experience with CX, with them ranging better than any breed I've ever had simply because they are very hungry. Here's a vid of the last large batch of CX...ranging and flying. This batch even roosted as high as 3 ft off the ground. They were fed once a day, fermented layer and whole grains, after they had ranged all day long. Pardon the very poor video skills...my very first such things and done on a still camera.
My first batch were raised by a broody hen and lived with the layer flock. They too ranged very well, all finished at good weights after only being fed once per day after foraging all day. Didn't lose any of either batch due to health issues or predators, though they ranged far and wide.