I had two roosters with 8 hens, and it wasn't enough. They were double teaming them too. Both were re-homed, and now my tiny OEGB cock runs with the layer flock. He looks pretty much like that video...LOL. But the hens have their feathers back on their heads now, and are very relaxed around him. He does a good job watching out for them all. He loves his big girls!!
I keep my Seramas in pairs for the most part. The males all pretty good to the girls. They seem to bond to each other reasonably fast, and the pullets stop trying to escape. If they don't struggle too much, then the mating goes pretty painlessly. I don't have plucked heads or bare backs.
Renee- if you don't care about having fertile eggs, you can replace the BW roosters with a little bantam rooster of some kind. You can have some eggs from my OEGBs if you want. Mine are very kid friendly, nice little birds.