Yeah, they're satin. All the yellow tris so far have been satin. I plan to do an outcross to a nice big standard fawn or red, or maybe one of each, in the next month or so, just to be on the safe side. These three babies have all the signs of being nicely put together meeces; the tails look long and strong, wide at the base, and the neat little circles of their ears are good as well. I was pleased to see a few cinnamons among one of my recent yellow tri litters, but not surprised as one buck of the original three pairs of meeces in that line was a nice big satin marked agouti (should say is, he's still very much alive, l'il ol' sweetie pot pie that he is). I believe that is where the dark red-orange on my tris comes from.
I wonder, are satin agoutis called 'golden agoutis' in some circles? I've newver been quite sure of that, though I've used the term myself on occasion.
Mondo, a huge yellow 'red' mouse, is a good candidate for an outcross, as are a couple of the standard fawns from recent litters.