How about your rooster(s)? I've not had anyone take care of my chickens and guineas yet in over three years having them. But when my son stayed with me for several months last year due to 'the virus' my rooster would attack him. The rooster obviously knew this guy was a stranger and a danger to his girls. I believe he would attack a caregiver. He jumped me the other night not knowing it was me. I was in the chook house and trying to get the girls out of the way to do something and they fussed and he ripped in though the pop door and jumped me. His spurs are trimmed and he can't do any harm if a person wears long pants but it is so scary being attacked by a rooster. I'm sure a caregiver would run and not come back. I have to come up with a way for chores to be done without Henry interfering.
Possibilities:
1) No more vacations while he's alive.
2) Automate as much of the set up as possible so caretaker doesn't need to go in except in emergency - i.e. have double the amount of food needed available and in place, a backup waterer, auto pop door, roll out nest boxes if you don't have external access to nests (so caretaker can pick up eggs from outside without ever going in).
I find 1 much easier but I'm mostly set up for 2 just in case.