I run my electric fence about 6-9 inches from the chainlink fence on electric fenceposts. Works for chickens but might be a bit close for ducks. On the run fencing where I have chicken wire, I use the 4" plastic extenders to move the wire away from the fence. In a do over, I would go to the 6" extenders. I use 3 levels of wire, 6-9" off the ground, 18" and 4'. Grounding the system to the chainlink was the best as the ground is fantastic and no problem with dry earth not provifing a good ground. (This will be in your instructions) The ground extends to the chicken wire as it merges with the chainlink at two corners.
This way, if a critter hits any electric wire and natural earth, it is shocked if the ground is not too dry. No matter what, the shock between the electric wire and chainlink/chicken wire is substantial.