They will not divide up they way you think they should: ten for you, ten for me, ten for him. There will be squabbles and fights, some serious, and some possibly deadly. A cockerel has to pick his flock from among the hens already "belonging" to a senior rooster, and the senior will not give them up willingly. The best way to avoid this is to physically separate the flocks with good fencing and housing, or to have enough acreage that they can separate into "tribes" as @Shadrach's did. But @Ridgerunner will tell you that with living animals you don't get guarantees, they are individuals and anything is possible. I had about 25 hens and raised up a very good cockerel as subordinate to my flockmaster. They mostly free ranged. It seemed to be working out very well. Until the morning I came out to find the cockerel dead. You just never know.