You need to separate them to keep your victimised drake safe. I have not had this with my flock of hundreds of ducks and rescued ducks. Ive heard of it but the only drake fighting I have encountered is a lot of mean feather pulling. However I have ahd drakes gang rape other drakes which is horrible. Your drakes injuries are not typical of that though.
I have just posted elsewhere asking anyone if they would find it useful to have a device that would possibly reduce or prevent drakes raping other drakes or ducks. This device might also help with drakes attacking other drakes, as long as the drakes were in a large or free range situation (it would not work if you had all the drakes together in a smaller area ie anything smaller than maybe 4m x 8 m.) If you would like to be updated on my progress testing out this little device feel free to pm me or looking up my other post in the ducks forum. I have been rescuing ducks since 2016 and as a result I have large numbers of drakes along with all of the fun and games that come with drakes during spring, and this is he reason I have been trying out this device the idea for which, I discovered by accident recently.
If i do manage to develop it to a point where I feel it is reliable, safe, and effective, I may look at selling it online, in order to fundraise for my duck rescue. If. It does work, it will be an absolute game changer for me, which is the main reason im thinking if it does i will look at selling it. As while i have bills of hundreds a week for my duck rescue, which mostly come out of my pocket, I am not very good at fundraising or just asking for money, but if thise little idea I am working on, pans out, then I know for a fact it will be a massive game changer for anyone who has drakes and struggles with the spring rape or aggression, but does not want to put the naughty drakes in the freezer (or even does not want to put all the naughty boys in the freezer). If it works out ill look at selling it online for a reasonable price to cover the costs of making and shipping it with a small margin.