How many roosters I need ?

that should be good i have orpingtons and usually it's said one rooster can handle 8 hens in there yonger years..........

 

I have to agree with LC orps. I think you are fine with three roosters. Just keep an eye out for excessive feather loss on the girls. If they are not being over bred and the roosters get along, you should be fine.

 

Well I'd probably go with two roosters myself, for that many hens. But it kind of depends on how your roosters get along. If the three you have get along well, then by all means keep all three. But if not, then I'd think two healthy roosters that the hens like should be plenty enough.