I have a Welsh Harlequin and changed my mind on the sex daily, what I found was the beak shape determined the sex as well as the husky raspy quack, the second picture I think you have 2 drakes at the back that I am sure of due to the bills,maybe 2 ducks at the front and 2 drakes in the middle, if you can turn them on their backs and locate the vent you will know for certain by sexing them this way, believe me there is no doubting the outcome this way as its clear to see. Wiki how has step by step instructions with images. My drake is 18 weeks now and is getting his green tint on his wings