ratios

Hey all! I'm a new duck momma of 2 Pekin drakes ( almost positive both are drakes ) they are I believe 10 weeks old. I'm ordering 10 Ducklings tomorrow to add to my flock! Breeds include Cayuga, Rouen, Welsh Harlequin, buff & black swedish..should all 10 be hens? That would make for a 1:5 Drake...