Mine are from Meyer Hatchery. I keep my birds solely as pets, so I'm not sure I can sell them as egg-and-meat birds. But, I will give you my honest experience with their production.
They lay fairly often, at least 4-5 times a week. They aren't super heavy producers and their eggs aren't the biggest, but they do produce large eggs according to my egg scale. They have both taken one or two short breaks to try brooding, but they have been the easiest birds to break in my flock and quit brooding within a few days of being kept off the nest. My girls are not as heavy as the breeder birds, that I'm relatively sure of. They at least don't look as heavy. They are, however, very meaty gals and heavy in comparison to many of my other birds. They are about 14 months old, so my experience is in the pullet stage (well, and 2 months of 'hen-ness').
What sold me on them is their personalities. They are calm and easily handled, have no problems with me working and moving around them. So calm, in fact, that I can pick them both up at once (as in, smush them together and lift) and carry them around if I need to, one under each arm. They are personable and sweet, sometimes just standing at my feet and looking up at me for attention. They would lounge in my lap for hours if I let them, just soaking in all the love they can take. I could go on and on...
Anyway, that's probably the best I can do for selling them, short of posting more pictures.
It's true what the first person says, they are really on shaky ground as a breed here in the U.S. There just isn't that much interest in them.
According to the Livestock Conservancy website, there are fewer than 1000 breeding Dorkings in the entire country, as well as an estimated global population of less than 5000. Another reason why I'd like to get into breeding them in the future--to preserve a breed that is close to my heart. If you couldn't tell, I'm passionate about these birds.
But I don't expect everyone to love them as much as I do.
Yes I do, SAVE THE DORKINGS!! I kid, I kid. But seriously--