You don't need to rehome them if you have enough hens for them. If you only have six chickens and three are cockerels and three are pullets, that's not going to work out; the roosters will be very hard on the pullets and the pullets will end up overmated, losing feathers, very stressed, and possibly even injured. Also, with a small number of pullets, the cockerels are more likely to fight over them. I would recommend at least 5-7 hens per rooster, so if you want to keep all three, you will need to get more girls. For three roosters, you should have probably 21 hens.