Dun is a simple dominant. One copy makes a gray that's a bit more "brownish" in tone.
Double dose causes a color called "Khaki" which looking at pics, is exactly like it sounds? I mean, it's not buff - it really is the exact same color as Khaki pants!
I haven't got Khaki in my birds yet - though the Dun Light Sussex (Cinnamon Sussex) rooster is in with a Dun / Brown hen right now. It's by default. There is a hen of mine who appears solid tan with dun tail, but she's a Mottled carrier, out of my Dun Buff Sussex hen and a colorful Aloha rooster. She's a great well-formed hen. The problem is, she's an escape artist, and I can't contain her in the main coop, she flies out. So she's in the breeder pen - ALWAYS - even though I don't really need to hatch her chicks right now, I just literally don't know where else to keep her, the brat.
Anyway, because of that, we may see a few Khaki chicks hatch in the next month or two. Dun, like Blue, only affects black pigment. So, I think we'd see maybe a brown hen, with a tail and neck that would be lighter in color than the body?!?
On the hen above, you can see the faint gray speckling, and the gray tail feathers. If she carried two copies of Dun, the gray tail would be khaki and the spots would be white with cream (Khaki) shading, instead of white and gray (Dun) color. We may need to wait until next year to see that effect!
Thank you for this. I'm color blind, apparently dun is not a very easy color for me to notice. I do like your descriptions though, especially of khakis... a brown bird with tan/light tail and neck would be a nice sight I think...
is there already a picture of the tan hen with dun tail and dun buff sussex?