Interesting. I’m sure he will crow soon. Maybe those mature hens are intimidating him and keeping him respectful. I have seen in my own flock that teenage cockerels harass pullets their own age, but the older hens don’t put up with that. I think it’s good for a cockerel to learn manners from...
He’s beautiful!
Do you have any other roosters? It’s not uncommon for a junior rooster to respectfully refrain from crowing in the presence of a senior rooster. I don’t think that would last forever, but longer than 7 months wouldn’t surprise me.