Hi, hope you are enjoying BYC!
The attack will escalate to when you aren't even doing anything and your back is turned.
Freeze his tasty butt and be done with it.

He can indeed protect the flock without being human aggressive.
If you aren't going to freeze him, then you should carry a stick and make him leave your area before proceeding. I also have a FBCM and he does not attack. Roosters *may* offer protection but they are often just a sacrifice to the predator. And any number of my hens can give predator warning... without crying wolf all the time like the boys do. The ladies get used to ignoring them.
How old are his so called "rooster" sons? So you have 4 boys and 6 gals? He is the dominant due probably to his maturity compared to the others that I'm guessing re still coming into their own and haven't YET challenged him. If my count is right... It's just a matter of time before them other boys start trying to breed and all the ladies will end up bald from too many boys clumsily learning to mate. Their protective hormones haven't kicked in yet as far as I can tell from your description. And their father is acting nasty.
That being said... you aren't his normal keeper and this is a whole new situation for him. Change is hard on creatures of habit. You MIGHT spend time training him and see if it works. See if he recognizes that you are the flock master and the giant who brings food daily. If you are new to chickens, I would get rid of EVERY single one of those boys and enjoy a hen flock for a while. How old are these daughters that you call hen? However if he attacked his previous owner, maybe they didn't disclose it and is why they ditched him. That information about his former behavior (if truthful) could help you make the right decision.
I got spurred by my FBCM
once when he was fence fighting another boy. I was stupid and stuck my leg down there thinking it would be a distraction. It just drew the full force of a
reaction from him which gave me a couple of bruises and 2 or 3 leg piercings from his punji spurs through my pants. I'm surprised at how much force his punch packed. It hurt and DID give me a new respect for what a predator MIGHT come up against. However, when my dogs start howling and when I approach roost
after dark (unknown predator)... he hunkers down into a corner if possible. Which I'm glad he chooses not to go after the dogs so far because that will be the day he meets his end here. Keep in mind I'm NOT afraid of being attacked and anyone who does so
willfully (and not of my own stupidity) will not be tolerated.
So cool that you got a flock!
You and your flock will IN MY EXPERIENCE be happier without the constant harassment of hormone raging males. (Trust me, the hormones WILL kick in). Good luck with your decision, every situation will be a little different and need to be taken on it's own merit. The learning never stops!
