I have 7 ducks (5 runners, 1 female Peking, and a drake khaki). 4 of the 5 runners seem to have a curly tail feather on their butt. I looked it up and read some posts here but is this a 100% method to sexing these 4 as drakes? I ask because in less than 24hrs I have found 5 eggs, but it looks like I have only 2 females in my flock. If I do in fact have 5 males, I need to re-home most of them as I purchased them for egg production.