I'm gonna respectfully disagree. Have you tried to free range white leghorns? They are the meanest, flightiest suckers, and very good at getting away. Granted, their hatchery-produced mixed breed descendants in black or partridge probably have an advantage in color, but just because a bird is...
I keep my eye on Welp hatcheries for when they have sales on CX at beginning and end of season. You can get chicks for ~$1.50 ea that way. Even their regular price ~$2.15-2.30 is one of the best I've found. Sometimes feedstores have sales too if they have trouble moving the CX. Decreasing...
Well, they're not efficient as CX, but as with many breeds, it depends on how you raise them as much as their genetics on how efficient they are. Type of feed matters (protein, etc), confined vs free range, stress (temperatures, predators), target days till processing, and target processing...