Edited by Johnboy 89 - 12/2/15 at 10:08am
Ideal's Cornish Rocks vs Cornish X - Page 2
Malay roosters go about 12lbs - and they're tall birds with big legs, and heavy structural systems.
A Cornish Cross rooster may go 15-20 if he survives that long and food isn't restricted too much - and he won't have nearly the bone structure - they're just not bred/designed for it. They're designed to get to about 8lbs as quickly as possible with as little food as possible - and they do that very well. It's irrelevant whether they live long enough to breed, because that's not their purpose.