Does he start just at day break? Do you have windows in your coop? If so darken them and it will keep him quit for a bit longer but I have found once they get a set time to crow they will do it at the sime time every day.
I have 1 red start that starts a 5:45 am like clock work and then I have a maran roo that starts to crow at 8:20 pm just like clock work every night it is like one says WAKE UPPPPPPP and then others says GO TO BED NOOOOOWWWWWW
Our boys crow whenever they are disturbed. So if a wild bird walks across the tin roof of the barn, they crow. If a feral dog barks in the fields around us, they crow. If the geese fly overhead, they crow. If they hear the train whistle, they crow. They also crow to say, "this is my territory"! You get the picture? Good thing my neighbors are a mile away!
The coop has no windows, he starts at about 5:45 in the morning and crows off and on all day. We like to hear him but the pre-6 wake up call is really annoying my dear hubby... Especially on the weekends.
I think I'll try some bales about the coop to buffer the crowing.... I always let my Roo Mario out at about 6:15 or 6:30 anyhow. But hubby would be less grumbly if he didn't crow til after 6. sigh.
Just tell him that over time he wont be able to hear them anymore. I barely notice my roos unless they are crowing at me while I'm holding them or looking at them