I X2 the Buff Orpington, although many different roosters could fit this bill. It will depend on your hens too, he may end up being only as aggressive as they are. You could always adopt a rooster 
We got our BO roo at an auction ( i felt sorry for him, he was older, but gorGEOUS!) We hatched a young BO roo and even at 8 mos, he is calm and protective. He has taken over his own little bunch of hens (his age)
I have heard many good things from the two people I know that raise Jersey Giants, the roosters are gentle, also have a neighbor that has a splashed cochin, largest rooster I have ever in my life seen and is very mellow. He isn't young, but very docile and friendly with all.
We got our BO roo at an auction ( i felt sorry for him, he was older, but gorGEOUS!) We hatched a young BO roo and even at 8 mos, he is calm and protective. He has taken over his own little bunch of hens (his age)I have heard many good things from the two people I know that raise Jersey Giants, the roosters are gentle, also have a neighbor that has a splashed cochin, largest rooster I have ever in my life seen and is very mellow. He isn't young, but very docile and friendly with all.
