There are three leg feathering genes. Two dominant, one recessive.
It also depends on whether the cochin is pure for all these or not. Typically a cross will have leg feathers, mostly on the legs and maybe a little bit on the outer toe. There can be surprises though, such as some looking nearly clean legged and some rather heavily feathered.
If you're hoping for clean legs after the cross.. it can be somewhat a project- the more genes you want to get rid of, the more chicks you will need to hatch. However you can possibly hit on one or two clean legs in the second and get better luck with that in the third generation.. but don't be too surprised if it seems mild leg feathering or stubs show up in some birds in later generations.