Be prepared for more overload, but I will try to describe the caponization rationale as best I can. There are definite advantages.
First, let me say that a Cornish cross is not really a candidate for caponization. They grow so fast that they don't mature sexually by the time they are butchered. In addition, they are difficult to caponize because of the body shape and fat under the skin. The RIR and other dual purpose cockerels are more appropriate candidates
The performance of caponization goes back thousands of years, particularly in China.
Caponization of a cockerel removes sex hormones from the bird, resulting in a docile bird.
Caponization prevents all of the secondary sex characteristics of the bird.....large combs and wattles, tough stringy meat, almost all crowing, aggressive behavior toward other cockerels, and sexual aggression toward pullets and hens.
An intact cockerel, as it develops sexual maturity focuses his energy on running around, fighting with other cockerels, chasing hens, and breeding. A capon focuses all of its energy on eating, growing, and accumulating muscle and fat within the muscle.
An intact cockerel must be butchered by 20 weeks of age generally to preserve the quality of the meat. After that time the meat becomes tough and stringy because of the effects of the hormones. Many young roosters at this age have achieved bone growth, but have not put on a lot of flesh on those bones(think teenage boy who grows 6 inches in a summer and is skinny as a rail)
A capon grows more slowly, maintains and continues to accumulate muscle and fat, and can actually be kept up to a year or longer if desired, with the ideal time of butchering 8-10 months. The end result is a larger meatier bird that has tender succulent flesh. A 16 week old capon may actually weigh less than a young rooster of the same age, but by the time they are 32-36 weeks old, the capon will most likely weigh more than the intact rooster, and the flesh will be more tender and succulent.
Depending on the breed of the bird, a capon can end up being the size of a small turkey. There are reports of a Jersey giant capon that weighed upwards of 20 pounds.....I can't even imagine! Capons are very popular at Thanksgiving/Christmas and are usually quite expensive. There is only one commercial capon grower in the US.
Capons can be housed together in closer quarters if need be. They can also be butchered as needed, rather than at a specific age. This is great in the event of some major catastrophe that results in no freezers available, or if you just want a large fresh chicken that will feed your family and guests.
I began caponizing this year, and though I have had slips(incompletely removed testicles, which regenerate and cause the birds to begin developing sexual characteristics, albeit at an older age. The quality of their meat is somewhere between that of a rooster and a capon. So those get butchered when the testicular regeneration becomes apparent.
I have capons that are 23 weeks old, have small pale combs, very docile and sweet. They are growing, eating, and doing great. I will most likely butcher them when they are 8-9 months old.
Here is a link to a caponization thread that gives a lot of information:
https://www.backyardchickens.com/t/675898/graphic-pics-of-my-day-learning-to-caponize
I hope this answers a few questions.
