It's the same diluter.
Fawn is basically a wild type bird(either black breasted red or Silver Duckwing) dilute by I^D, two copies are called Sports. So only the heterozygous are shown.
Silver Fawn Sport.(nearly white due to Silver and Homozygous Dun)
I Wish I had the resources, patience and enthusiasm of MysteryChicken she truly believes that she will complete most if not all of her projects. That gets her out of bed every day with a smile. I wish I could be like her. But I am an old grumpy pessimist instead.
I am not sure where you are getting your information from, but Dun is Anything but very rare in any part of the world.. It has been like that for the better part of 30 years that I have follow Chicken breeding/Genetics.
Platinum on the other hand(the combination of Blue and Dun) is vary rare...
So you are saying that Khaki and Not recessive Chocolate is Practically non-existent in the USA?
I believe most Chocolate Colored birds in the USA Are heterozygous Dun(until recently) not until recently that recessive chocolate has made it's way to the USA from UK.
I've come across a breeder that breeds 3+ feet Giant Brahma and was able to get a 2 month old cockerel, I always thought how would a full sized brahma with silkie feathers would look, they are massive birds so I just can't breed my new cockerel(when mature) to my Silkies, perhaps Artificial...