I have a junior rooster in my flock, a yr old Lavender Orpington that weighs about 13-15 pounds. He's a moose but a beautiful moose and as solid built as a rock. I cracked up one day when he tried to approach one of my diminutive Welsummer hens to mate. She immediately voiced her unwillingness to submit to him and when she screamed out her protest, it startled him and he let her go. Instead of making her escape, she turned around and gave him a hard peck and then chased him across the run trying her best to peck him again as if saying "WHEN I SAY NO I MEAN NO!"
It was simply hilarious to see this little hen half his size if not less chasing down this Arnold Schwarzenneger-ish rooster and giving him a piece of her mind. By that time the flock Alpha Rooster had intervened, attracted by the racket and took over the attitude adjustment. Poor boy just didn't have a chance so I'd say it's probably normal for the girls to protest at times if the rooster's attentions are unwelcome.