Fascinating thread. I've never seen a roo mate a broody. I have had only bantam brahma roosters (and hens of various breeds), and have seen them mate only hens that are laying or about to start laying. In fact, I can always tell when a pullet is about to start laying, or a hen about to resume laying in late winter, by watching for rooster's behavior towards her. I've often wondered what triggers him. Is it her behavior? Does she squat more readily when about to start laying? This seems likely, yet the roos seem to "rape" even those hens who do not squat and try to resist, as long as they are laying. Could there be a pheromone that tips him off? Would be unusual in the avian world.
Further, I've noticed that my roosters preferentially feed hens that are laying or about to start laying. Those not laying often get chased away from tasty morsels. Those boys know what they're doing.
My chickens are confined in the coop/runs for part of the day and free range for part of it.