It depends on if you want fertile eggs, and/or protections.
The thing with roosters, there really are no rules, as in if you do this, that will work. They are 'sometimes' addition to the flock.
Sometimes a single rooster can cover 20-25 birds, and will have the hens all have fertile eggs. Sometimes only 10-15. Sometimes less than that.
Sometimes you will have 10 hens per rooster, and you won't have bare back chickens, sometimes you will.
Sometimes you can free range, and roosters will protect them from predators, some will and some won't.
So is 6 a good number for 100 hens - well I think it is a reasonable place to start. As you eat eggs, always keep a tally sheet on the counter - marking fertile and non fertile eggs. If the non fertile egg percentage starts to rise, you need younger roosters or more of them.
Mrs K
