I have been raising chickens for 8 years and almost every time we butcher, the meat is tough. Am I butchering the wrong kind of chicken? Not processing fast enough? Are they too old/young? We've butchered Brahmas, wellsummers, and black marans. Really just any good size rooster. We typically butcher at 7-8 mths. We want to eventually sell to the public but there's no way I'm selling tough meat. Please help!