I was disturbed by the dismissal of a poultry man of 35 years experience opinion but everyone's opinions here on BYC is right as long as it coincides with what someone wants to hear. And somehow not anecdotal.
I can state that I have 35 years of raising chicken experience (as I do) and the truth is my experience is the same as anyone else's experience it's just anecdotal evidence nothing more unless it contained controlled scientific study... Using anecdotal evidence to counter scientific studies is a fallacious why do you find that disturbing?
Only 1 of the linked studies mentioned or was specifically done on cocks.
I simply posted a few examples and suggest you research it further yourself...
In the end it's your birds, you do what you... Pointing out both sides of an argument and letting others make an informed decision is never bad...