For anyone else that's willing, try this basic plan:
Lav Orp X Black Cochin = F1
F1 X F1 = 25% Lav in F2
Choose Lav F2 that are most "Cochin-like" and proceed with them. Cull the rest.
Lav F2 X unrelated Black Cochin = F3
F3 X F3 = 25% Lav in F4
Choose Lav F4 that are most "Cochin-like" and proceed with them. Cull the rest.
etc.
When working with a recessive mutation, you will need to cross the F1's (and all the other F's with an odd number) together to get visuals. If you are starting with one Lavender, the F1 you breed together will have to be siblings, but after that, you cross to an unrelated Cochin in the next generation. If you have several unrelated Lavender, you don't have to inbreed at all. You'd just do F1a X F1b (the F1 from one Lav crossed to the F1 from another Lav). When you breed F1 X F1, you will see a range of type from "mostly Orp" to "mostly Cochin", but this range will keep moving more toward "mostly Cochin" with each generation being bred back to a Cochin. Don't breed back to the original Lav or any previous Lav generation -- just keep moving toward "more Cochin." I don't know how many generations would be necessary to bring type back completely, but breeding to a bird with more Orp will just set you backwards.
Hope that helps people interested in starting their own project.
