That's long enough that there would be some bickering each time the male returns to the other bachelors. It seems unnecessarily stressful for all. Plus, you would have to wait for the hens to be rid of the previous male's sperm, and then repeating that cycle over again
Well, yes. It would be less stressful for all if you kept each pen with its respective male. If you'd still like to switch the males around, keep it to a minimum