We have two Khaki Campbell drakes who have taken very much interest in two of our Pekin hens. I have observed both of them at once trying to mount one of the Pekins continuously. One of the drakes was standing on her back with her neck pushed to the ground and the other had her by the neck and was trying to jump on as well earlier today. We have also noticed recently that this particular Pekin is limping and seems to have broken or sprained her leg. It's not like she is the only female. We have two Khaki Campbells, one Runner, one Golden Cascade, one Buff Orpington and I'm not sure how many other female Pekins. What can we do to make sure they don't kill or injure her?