Call duck drake to hen ratio

[Hardboiled]

I hatched 10 call ducks around easter and 9 of them are drakes. I'm keeping my one hen and the drake she's chosen to pair up with, but I want to keep a couple other drakes. How many more hens will I need if I keep 3 or 4 drakes total? Pix of my girl Smily with her drake for tax.

 

[Logar]

Your ducks are super cute!
@RossAcres may be able to help

 

[RossAcres]

Oh boy. That's a rough hatching ratio lol. Honestly, you should have at least 2 hens for each drake.