Some young roosters will not crow if there are older, stronger roosters around until they feel like they can compete with the older roosters, in other words the Red wants your rooster to think he is a hen. My roosters did this to, when I got my Black Australorp rooster as he matured he started to crow, I introduced him to the main flock but then he stopped crowing. I was clueless to why he stopped because he was crowing like crazy a few days ago when he was in his own pen. Then I realized that he was also not trying to mate with the hens. As I watched closer I caught my other two roosters attempting to mate with the Black Australorp multiple times, the Black Australorp would never let them successfully mate but after this I realised that the other two top roosters were fooled into thinking the new rooster was a hen, despite the fact he was much bigger than both of them and had a fully grown crown. A few months later as the new roo grew his spurs in he started trying to mate with the hens, he still was crowless but the other roosters caught him mating and beat him up, he was not tricking anyone anymore. The new roo was placed below the other two and only after he was discovered to be a rooster did he start to crow again.