There are a whole lot of myths and urban legends on this forum about roosters. They are living animals and you cannot be sure of what they will do. You are never assured of having problems, but the more you have the more likely you are to have problems. My recommendation is to get rid of two of them and do it pretty soon.
1. How long will the rooster get along together in the coop? They only free range about 2-4 hours a day.
This depends a lot on their individual personality and on what you call "get along". The six chickens have been raised together and at three months they have already established a pecking order. You should be seeing the roosters squaring off and fighting. This is flock dominance, not pecking order. A lot of the time, when they are raised together, this flock dominance fighting is not much. They square off, one quickly decides he is outmatched, and he runs away. It really helps if he has enough room to run away. If space is tight, he may not have that option. This does not always happen though. Sometimes they fight to the death. They are living animals. I cannot tell you what they will do in your specific circumstances with those specific roosters. I free range mine and have never had a serious problem with multiple roosters coming of age, whether all are the same age or if there is a dominant rooster in the flock. They actually form a pretty good team in taking care of the girls with different roosters having different responsibilities. Sometimes there are minor skirmishes to remind them which one is in charge, but this is mostly chasing, not fighting. But I'll say it again. Some roosters fight to the death.
2. I assume that I will eventually have to send at least 2 of the roosters on down the road. I can't eat them myself and can't stand the thought of someone else being cruel to them. Any suggestions as to where I send them or find homes for them?
Once you let them go, they are out of your control. You can advertise on Craigslist or Freecycle, maybe put up a notice on the bulletin board of your feed store, and try to find someone who you think will give them a good home, but once they are gone, they are gone.
3. Is one rooster too much for my three hens? My grandma said he will run those hens ragged! And if he does the fertilize the eggs, if collected the day they are laid, can you still eat them?
A fertilized egg is not going to develop unless it is at incubation temperatures. If you collect them daily, even if they are under a broody hen part of the day, they will not have developed. I always crack the eggs in a separate bowl anyway, but this should not be a concern for you.
Many breeders keep one rooster in a pen with one or two hens and don't have them run ragged. Some people have hens that are run ragged with one rooster and 18 or more hens. Some people on this forum report running three roosters with two hens and not having this problem. There is no magic ration of hen to rooster that guarantees you will have this problem or that guarantees you will not have this problem. Run ragged generally is taken to mean barebacked hens. That is where the rooster removes the hen's feathers in the small of her back with his claws and spurs while mating. He can wind up cutting her, which can be a fatal problem for her if the other chickens see the blood and raw meat and turn cannibalistic. A hen losing a few feathers during mating is not a big deal. But if the area starts to get bare, it needs to be addressed. And if you ever see any cuts, get that hen isolated before the others kill her.
Without going into great detail, adolescent roosters are usually a lot worse about this than adult roosters. Their hormones are running wild, they have no self-control, and the hens or pullets often do not willingly agree with their intentions and resist. I think the odds of you having serious problems with three adolescent roosters with three adolescent hens are tremendously high. It is not the potential fighting between the roosters that causes me to suggest you get rid of two roosters soon, but the risk to your pullets. In spite of anything else I say here, I do think the fewer roosters you can keep and still meet your goals, the better off you are.
Will one rooster be too much for three hens? Maybe and maybe not. It depends on a lot of different factors, the personality of your hens and rooster being the most critical. I think that you have a reasonable chance of seeing some problems while they are adolescent, but if you can get them through that period, there is a pretty good chance the will be OK together when they mature. Some of the things you can do to help them get through this period is to put aprons on the pullets of they become barebacked and trim the claws and spurs of the rooster. I don't mean remove the spurs and claws, but blunt the sharp end. If you cut too deep, you get into the quick. I think the claws are more important that the spurs since a lot of the bare-backed problems occur when the rooster is young and the spurs have not yet grown in.
Hope you get something out of this that is useful.
