Female ducklings question

[BrookBottomFarm]

Hi there! Last year, I bought 2 Khaki Campbell ducklings who ended up both being drakes. As the only two ducks I had at the time (and a large pond & yard for daytime free ranging), they haven't had many troubles together. No aggression, and they seem pretty bonded. This year, however, I decided to add some hens into the mix, and bought 6 sexed ducklings (female) from Cackle hatchery. They are about 5 weeks old now, and have been living in a separate fenced off house & run next to our pond. I have been feeding them along with the male ducks at the same time each night, on either side of a common fence, and they seem used to each other now. The ducklings are quickly getting their feathers, and of course have grown so much. I don't plan to put them together right now, but have been wondering lately at what age is it safe to do so? My biggest concern is that the drakes will immediately try to breed them, so I want to make sure they are old enough. Any insights?

A couple more things while I'm here:

-Do you think 6 hens is enough to keep with 2 drakes who seem to have gotten along well so far? Will the presence of hens make them more aggressive do you think?

-Has anyone ever had a crested Khaki Campbell hen? One of the ducklings came with the tiniest little poof ball on her head, and as she has been feathering out, it's evident that it's not going away. I'm sure she's going to be cute, but I've just never seen a khaki with a crest! If you have had one, any photos to share? I'm including a photo of her (we call her Dolly) from a couple weeks ago.

Thanks!

 

[Miss Lydia]

You may have to make her a helmet that is going to be yanked a lot and there isn’t skull under it. Thankfully it’s small.

 

[Texag87]

I think the general rule is 20 weeks old before they can be with drakes, maybe 21 or 22