Here, they're separated only if the boys are bothering the girls.
I like to breed for roosters that are not so forceful- courting the hens etc. The ones that just grab the girls whenever they feel like it usually are culled.. unless there was an exceptional something about him for breeding later or is placed with older, in lay hens then he's culled after.
It's so much nicer to see a flock where the hens are either actively following the rooster or they are not worried if he passes by. The breeding usually happens only when the hens squat first. Bothers me to see terrorized hens.