Hi, we have split/black orpingtons.... I'm not sure if you're referring to our listing or not but here's the statistics (sample was on a group of 30+ hens - ours is a smaller flock so the percentage results may be a little different:
As our listing says "Babies from Group #2 will be visually black or lavender. In terms of genetics, Split x Spit will yield on an average 25% Lavendar, 50% Split Black Lavendars, and 25% Black Orpingtons. This means they will be either black or lavendar to the eye. The lavs will breed true , the 50% refers to those that will carry the Split Black lavendar gene and the other group is purely a Black Orpington (not carrying the lavendar gene)..
Hope this helps....Nancy