I have done both. Since I have limited space, I didn't want to risk extra boys with one of my first orders and paid extra to have them sexed. Now that I have actually butchered a few ducks, I don't worry so much. I eat the extra boys.
I just got 14 ducklings from Holderreads 5 weeks ago, they do not sex their ducklings. Out of the 14 I can only hear 2 quacking. 1 of them is LOUD, 1 is just learning...I hope to God I have more that will quack or I will be selling or giving away alot of nice drakes.
I've got 11 straight run WHs from Holderreads as well. I don't have the $ to shell out for sexed ducklings so I went the route of SR with the intent to sell off extra males at a slight profit. Heck, maybe even break even. *shrugs*
My first experience with straight run was 25 males out of 25. It happened to be a hatchery that sells sexed, and I am suspecting that they pulled some females out and sold them and then whatever was left got sold as straight run. It seems to me that 25 out of 25 is more than bad luck.
I just bought some straight run hatchery ducks and they are intended for my freezer, so I don't care what sex they are.
I also just got 10 from Holderread, but he doesn't sell sexed ducks, so at least I know he didn't sell the females and ship the remaining males as straight run. I will eat the excess males. Those will be some mighty expensive roast ducks.