I love this breed and I'm setting up clan breeding pens so I can keep them long term. They are often divided into two groups: first imports and second imports. The first imports are closer to standard, but Greenfire brought in a second import when the first imports were showing inbreeding fatigue. The second imports do not follow the standard as closely.
This breed should lay 200-250 eggs per year and they should be true green eggs, not blue. They can range in shade, but the preference is the Moss green eggs. They also often have speckes and, let me tell you, their eggs are beautiful!
Breeds that likely contributed are Rhode Island Reds, Australorp, Cream Legbar, and New Hampshire. Silverudds Blue should have dark eyes, slate legs (or willow for splash), yellow skin, no red leakage, lean body type, no leg feathering, and no crest. Comb points should be even and it is preferred that males have gold or silver "birchen" while females are solid, though it is acceptable for males to be solid and for females to have birchen. Males should be around 5.5lbs, females around 3lbs. It is also preferred that they mature quickly and I can usually tell my male chicks from my females by 4 weeks old. All of this should breed true.
Like NatJ explained, their color does not breed true, but they only come in BBS coloring.
They should be vigilant and are good free rangers. They are not usually flighty and most of mine will readily come up to me to peck at my pant legs to demand treats. They're a joy to have!