Drakes and ducklings

So I have 2 drakes and 3 hens, all adults. But I recently got 3 ducklings. They're now about 7 weeks old, fully feathered and quite big and I've had them in a movable run that sits inside the larger run to keep them separated from the older ducks for about 2 weeks, putting them up in the pen at night where the older ducks can't reach them.

However, a few days ago I took them out of the movable run, because I want my mean rooster in there until I can re-home him. I'm tired of his aggressive attacking and stripping the back of my hens. BUT, now I have my 2 drakes going after my 3 ducklings. Mostly it's just the one, or so I thought. My Cayuga, grabbing the back of the necks of the Cayuga babies and looking like he's trying to mate them. I stopped that quickly and penned him, and opened the run for free- roaming so the other ducks can run off across the yard to play in my neighbors ditch and my ducklings can have some space, I then walked my adult Cayuga out with the other adults and released him with them so he wouldn't have reason to go after the babies again. This works fine, it seems, as long as they can free roam the whole yard. The babies have plenty of places to run off to and the adults have certain favorite areas. But today it's going to rain, I have to keep everyone in the run because not only do I have 7 week old ducklings that might not know to take shelter in the storm, I have almost 12 week old chicks who are still learning to free-roam, too. &My adult Cayuga went straight for the babies AGAIN. I put him in a dog crate for a bit, and walked away, just to hear my babies screeching and my adult crested Pekin going after them this time. Now they're both in a dog crate, but can't stay there all day.

I don't mind separating the run, but I don't know how to do it alone and any time my husband has had his weekends we've gotten rotten weather these last few weeks.

How long can I expect these males to keep going after these little ones??

My two adult males (minus the mallard, he was re-homed):


My 3 babies:

It all looks pretty open in the pics. Do they have cover they can dive into to get away from the adults?
Try tossing some large branches in there that have a lot of little branches on them so the young ones can get under and the adults would have obstacles to get around in order to reach them. Maybe even toss a tarp over most of it so they are out of sight out of mind. I think you could anchor the tarp with tent stakes or heavy rocks to help keep it in place.

Leaning up some scrap wood will also help if you don't have any branches you can haul in the pen.

The first picture is the adults free roaming a while ago and the 2nd one shows the babies when they were in the moveable run. Right now the babies are diving for the wheel burrow of dirt, but my pekin dove in there with them before I grabbed him out. I like the branch idea! I'll have to see what I can find, plus it'll give my younger chicks something fun to play around on. Here's what the run looks like:

I think the cover for them should help a lot. I know when I had ducks the Pekin was the worst one in my group for harassing the young. I did have a large gander that had no patience for such goings on so did not have to worry much with him on guard duty.

That's just it, it's usually my Cayuga chasing everything and grabbing it, and my Pekin that chases the Cayuga and grabs HIM. I thought it was just my Cayuga harrasing the babies, but when I walked away after putting the Cayuga in the dog crate and saw the Pekin going after the babies next... ugh. The babies ARE fine with the girls, though. They were out playing when I went out ot make the safety area and the girls just ignored them.

I put the stick barrier up around the dirt burrow since that's where they were already running. I'll go out and check on them periodically and see how it holds up against the big ones.

That looks like it should give them some good cover!