Thing is, rooster do NOT understand sharing. And if you have 3 roosters and 30 hens, they will not split them up, allowing this rooster to have these, and that rooster to have those. Each rooster will want ALL of the hens for himself... and that can lead to fighting.
Roosters are a crap shoot, and even though they are perfect, friendly gentlemen right now that seem to adore you... it can and often time does change. So ALWAYS have a plan B. A place to separate roosters, and it should be set up and ready to go. They call it rooster fighting for a reason. Some fight once, some fight to the death, and some fight somewhere in between.
As Awakening Forest put it, she/he has several different groups of roosters and hens. She keeps them separate. If you have that many pens, well then you are probably going to do fine, for the most part.
Some new people come on here and think everyone will just get along if there are enough hens, and that is not how it works. They won't all just be nice. A lot of roosters can be VERY mean.
Mrs K