I didn't, until the gal at my favorite feed store asked me if she could buy some fertile eggs from me for her rooster-less broody hens. She didn't care that eggs from my flock are all mutts - she just wanted to make her girls happy. I have given some to my good friend HHandbasket now and again, but never sold any until recently.
The eggs are so fertile the feed store gal has asked for a dozen more, twice, and for a half-dozen for a friend of hers with broody hens. Her hens hatched 11/12, 10/12, and we'll see in about 2 weeks how the last dozen does. I sell 'em to her for the same price as eating eggs, because they aren't any pure breed. I added a bantam egg once, for fun, and her daughter was THRILLED it hatched out a cochin mix bantam.
Oh, and I deliver these eggs when I make a feed store run.
I don't want to get into shipping eggs, because I have incubated a couple hundred eggs shipped TO me over the past year or so, hatching about 70 or so chicks..... That's how I get the pure breeds, but then I let my flock range freely and breed freely.