A few years ago, I had two chicks hatch from a clutch a broody sat on. One pullet and one cockerel. The cockerel used the pullet as constant "practice" from the time they were four months old, and the flock rooster pretty much ignored her. By the time both were a year old, the little female looked like a doggie chew toy from being constantly mated.
Conclusion: as
@Fueron says, it doesn't always matter what the ratio is. In my pullet's case, she was just as overmated with one cockerel as if she had a fleet of roosters after her.