I have had chickens for about 10 years. I do not free range my chickens as the hawks will get them. They are housed in different pens. My ratio was and is usually one rooster per two to three hens as my enclosures are only 12x10. None of my roosters ever beat up on my hens and the hens rarely lost any feathers. In the photo you will see my rooster named "Rosey". He lives with two hens. The backs and feathers on his girls are perfect. To me, it seems some roosters tend to be more gentle than others. My roosters are Ameraucanas. In the ten years of having chickens, I have had the same ratio, one rooster per 2-3 hens. Always worked out fine. I don't know about the different breeds. I can only tell you my story.
