Steel E(s) is a more advanced subject in color genetics discussion because the appearance is not very obvious. The best way to identify it is at the bunny stage.
|These three bunnies all have black skin at birth. The two on the right are fairly easy to distinguish one from the other. |
The one on the right is chestnut agouti, A-B-C-D-E-, at birth, the back and the side are black but the tummy is pink and the inside of the ears is also pink.
The middle one is a black aaB-C-D-E-, the entire body including the tummy and ears are all black at birth. When the fur start to grow, the black stays black but the chestnut will show brown/tan mix with black all over the back and side while the tummy turns white or very light tan. In addition, the eye cycles and half moon under the nose all become visible.
The one on the left look totally black at birth then then it'll show some brownish color underneath. The tummy and the back are similar color. It's an indication of the steel gene, --B-C-D-E(s)- It could be a self steel, then aaB-C-D-E(s)- and it could be an agouti steel A-B-C-D-E(s)-
|The same three bunnies, from left to right are chestnut, black and steel.|
|The tummy of a steel looks about the same as the back.|
|A junior steel.|
|An adult steel mainly identified by the mask. There should be tip colors to indicate steel but it's hard to see in a photo.|
The order of dominance is steel E(s)-, extension E-, non-extension ee.
If you have fawn or tort, you can be sure there won't be any steel as ee is recessive to it. Though extension E is also recessive to steel E(s), it's a lot harder to tell in wool breeds.
Since E(s) is dominant of E and ee, if your herd does not have steel, it won't "pop up". Unless acquired via an outside animal, you are not going to get a steel.
The breed being used in the above illustration is French Angora.