The same could be said about dogs, and roosters, for that matter.
You can say that again, I had a rooster that was nice as could be and would sit on my legs next to the pullets... then one day the switch was turned and Henry became the meanest rooster I've ever seen to people and chickens. Eventually after I tried everything I could think of Henry had to go to freezer camp.
On the other hand my neighbor had a huge white rooster with 3" spurs and every time he saw me he would come running up to me as fast as he could and stop 2' in front of me and he would follow me into the machine shop right behind me and I'd get a bowl of food and go back outside with Rooster Cogburn following behind me. I'd sit on the step and put the bowl in my lap and he would eat till he was full then wander off until the next day.
JT