Roof Rat Bait Suggestions

Hi All,

I set up a bait station for night hunting Roof Rats. It’s in a nice safe spot to take a shot at them but it’s not positioned directly on one of their main routes. Their main pathways are on top of the chain link fence on either side of my property, not ideal for a safe shot. I’ve set up snapper traps with peanut butter, sardines, pop tarts, dog food, peanuts, little pieces of various fruit, and had varying luck. It seems like they go for it one day then are done with it. I also wash the traps and wear gloves so I don’t get my smell on them. 
Anyway, I’m trying to draw them to a bait station to shoot them at and wondering if anyone has a “magic bait” for these California Roof Rats. Thanks
 
I was dropping my daughter off at a friends house once and noticed they had large height metal rings around all the palm trees surrounding their house. The man said that they helped stop the giant rats that were getting into their house. The rats would climb the trees and drop onto their roof and then somehow found access points to get inside. Once he put up the metal rings it kept them from climbing up the trees. My uncle had the same issue, we could never figure out how they were getting into the attic.