If there are multiple roosters on a farm, living in the same coop or different coops within hearing distance, they will trigger each other to crow earlier, like it's a competition.
Especially young roosters will try to establish themselves by being first. The big old rooster who knows he is the rooster in the henhouse can afford to wait, with his big testes energy.
Yeah, my roosters get started 1-2 hours before dawn, and they'll crow now and then throughout the day for various reasons, usually something like, "Hey, stay away from my hens, buddy."
Hens are pretty quiet. They'll do some clucking after they lay an egg or when one of them finds a worm, but you'd have to be a very sensitive neighbor to be bothered by their nose.
Especially young roosters will try to establish themselves by being first. The big old rooster who knows he is the rooster in the henhouse can afford to wait, with his big testes energy.